Achievement Breakdown: (50)
Story Related: (2)
Missable: (13)
Secondary Objectives: (13)
Collectibles: (2)
Slay: (13)
Miscellaneous: (7)

All Achievements in Black Mesa can be unlocked in a single playthrough, though we will have to reload previously made Saves to earn alternate Achievements. There are no Achievements associated with Difficulty so play on whichever you like. I very strongly recommend just playing on Normal as there are some pretty irritating Achievements we need to unlock; increased Difficulty will only make a bad time much worse.

There are a high amount of Missable Achievements or ones that have very specific conditions to unlock. The vast majority of them are extremely straightforward, you just need to be aware of them ahead of time; this will all be covered step by step in the guide, so you do not need to worry too much.

The only Achievements related to Collectibles take place on Chapter 15-17 so the game will slow down a little bit as we go about finding them.

The Achievements that will give us the most grief are the Pepperoni Precipitation Achievement & The Rarest Specimen Achievement. If you have previously 100% Half Life 2 – Episode 2, you will be familiar with the Little Rocket Man Achievement… these two Achievements are exactly like it, but way worse as not only do we not have a Gravity Gun, but we have to juggle two different objects. Once we collect them, they must be taken from their prospective Chapters & taken right to the very end of the game. Just great.

I won’t lie to you… this is a pretty hair pulling 100%. I wrote the guide under the pretext that you will be taking both Items along with you at the same time. While this cuts down on your game time overall, it also adds on a lot more grief. This entails A LOT of reloading, a lot of frustration, & a lot of replaying the same “puzzle” over & over again. Doing this severely undercuts the enjoyability of this game, which is criminal, because Crowbar Collective did an absolutely outstanding job remastering Half Life 1. You may consider playing a playthrough unlocking all other Achievements, then reloading Chapters 4 & 7 to re-beat the game with the two Items.

Some things to note about our dreaded Items:

The Hidden Hat:

The Hidden Hat can float in water & can be thrown pretty far; it is very light. The biggest annoyance of it, is that it rolls, meaning you have to be very deliberate with where you put it down. Ideally, you can rest the hat on its top of bottom, but that can be tedious to do if it doesn’t happen organically. The Hidden Hat frequently rolls under places we cannot get to or clips through the floor in places that we will not be able to see.

It is very difficult to take up ladders, & because it rolls, if it ever gets knocked out of your hands it usually ends up falling over ledges or out of bounds. Because it is so light, so explosives have a good chance of blasting it far away. Lastly, it can be prone to vanishing completely after passing through Loading Screens if it is not held directly in our hands at the time. This does rarely happen, but it does more than you would want it too…

In certain areas of the game, we cannot backtrack meaning if you are packing both Items, you can only bring one of them forward. To get around this, the best strategy for getting the Hidden Hat across gaps we cannot jump back across is to “Shotgun-punt” it. You throw the hat into the air & then quickly shoot it with the Shotgun. If done correctly, it will get launched across the gap & land on the other side… then it is just a matter of luck praying that it does not roll backwards off the ledge.

The Pizza Box:

Opposite of the hat, the Pizza Box is very heavy. It cannot be thrown very far & it sinks in water. As a plus though, it also does not roll making it much safer to handle… unless you are going up ladders. Ladders are especially difficult with the Pizza Box due to how bulky it is.

For some ladders, you can throw the Pizza Box up the ladder & if you climb up right behind it, you can smack it up the ladder using the Crowbar. This definitely helps a lot, but also brings its on problems.

For those interested, here is an organized list of all the Achievements/Secret Achievements. This is how I derive my Achievement Breakdowns & the first reference I create before I begin my 100% journeys.
https://steamproxy.net/sharedfiles/filedetails/?id=2974305434

Before You Play!: Black Mesa only has partial Controller support. For the most part, you can play the game just fine; navigating the Main & Pause Menus may still require a Mouse. If you are having issues with your Joysticks not working, go into Options – Game & turn on the Developer Console. Then press the ~ button to bring up the console & type in “joystick 1” (without the quotations around it). Now your Joysticks should work fine though you will probably want to increase your Vertical & Horizontal Sensitivity.

This happened to me a few times when I hit Chapter 17, the button inputs for my Controller would stop working. I could move the sticks just fine, but none of my button inputs worked. To fix this, press ~ to get to the Developer Console & type “exec 360controller’’ (without quotations) to rebind your controllers & fix the problem. This resets your Sensitivity so you will also have to adjust it back to your preference.

*Guide contains major spoilers.

1. Chapters: 1, 2
2. Achievements: 6/50
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Take the tram ride… equally as long as it was in the original game, into Black Mesa.



Achievement #1 – Proverbial Tinkerer: Interfere with the alarm & laptop in Anomalous Materials.
Exit the tram & security will let us into the main reception area of Sector C. From where we enter through the blast doors, look off your left in the corner of the room to find a laptop with an open email to Walter Bennett. Interact with it & a Scientist will come tell us to stop.

Now walk over to the reception desk & a Security Guard will speak with us. When he is done talking, walk around behind the desk & look underneath it to the Guards left to find an Emergency Fire Alarm Button. Push the Button (you may need to Crouch) to set the fire alarm off & unlock our first Achievement.


Achievement #2 – Convection Refinement: Ruin the microwave casserole.
Leave the reception room now & begin heading down the hall following the green lines on the wall to take us to the Personnel Facilities; it will be two rights down the hallway. Enter into the nearby breakroom & we can find a microwave on a counter. Interact with the microwave, & let the casserole inside cook for a few seconds until it explodes… unlocking our Achievement.


Achievement #3 – Caffeine Extraction: Perform surgical caffeine extraction from 20 machines.
Make a Quick Save in the breakroom now & approach the vending machine that a Security Guard is leaning against. Interact with it to have a Soda Pop come out of it; do this 15 times & all the lights will go red & the machine will be all out. Reload your Save now & interact with the vending machine another 5 times to unlock our Achievement.


Achievement #4 – Brownian Motion: Pass the toilet paper to the Scientist in need.
Next on our to do list, keep following the green line along to reach the lab change room. Before approaching the HEV Suit, go to the opposite end of the change room to find some bathrooms. When we enter, we will hear a Scientist in trouble as they have run out of toilet paper going number two… Walk over to the sinks & grab the roll of Paper Towel on the counter; take it over to the Scientist & roll it under the stall door to them to unlock the Achievement.


Achievement #5 – Less Than Desirable Consequences: Die in the AMS beam before starting the experiment.
Collect the classic HEV Suit & make your way to the Development Anomalous Materials Labs. Make your way through the labs until you reach Test Lab C-33/a. After speaking with the Scientists outside it, make a Quick Save!

Enter the Test Chamber, & climb up the ladder to turn on the rotors to the AMS. As soon as they start spinning, climb down the ladder & walk over to the machine. When the beam begins to fire, step through the beam & kill yourself to unlock the Achievement.


Achievement #6 – Resonance Procrastinator: Refuse to insert the specimen into the Anti-Mass Spectrometer.
Repeat turning on the AMS rotors, but this time wait for the specimen to arrive. When it does, do not insert it into the AMS beam & instead wait for around a minute. The AMS will go critical, killing us again, but also unlocking the Achievement.

With this done, insert the specimen into the AMS & complete Chapter 2…

1. Chapters: 3, 4
2. Achievements: 10/50
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Achievement #7 – Prophylactic Suggested: Get overtaken by a Headcrab's ample anterior.
When we come to, leave the Test Chamber & begin making your way back up to the surface. After Eli opens the door for us to continue, & the AMS beam blasts open the next door, we will head up a hallway to a flaming room where we can see a Scientist stumbling around on fire. Make a Quick Save.

Head around a corner, & a Headcrab will appear through a portal in front of us. Let the Headcrab do… what it does, & kill us; depending on how much health you have, you may want to increase the Difficulty for this Achievement so we die faster…


Achievement #8 – Inflammatory Actions: Kill a Headcrab using fire.
When we make our way back to the Sector C reception room, make a Quick Save. If you have a Security Guard following you, speak with them to get them to hold position. Grab one of the Flares on the reception desk & quickly slip under the exit blast doors. Look off our left into the small security checkpoint & the window will be broken with a lone Headcrab inside. Quickly either throw the Flare at it, or jump into the checkpoint to hit the Headcrab with the Flare so the fire kills it.

If the Security Guard kills the Headcrab, reload your Quicksave & try again.

The Hidden Hat: Now… already… we will encounter one of the worst elements for our 100% run. From the reception desk in Sector C, make your way out towards the tram station. Make a Quick Save here.

In the tram station, head over to the righthand side along the railing & we can spot two large pipes coming out of the wall. Jump onto the railing & carefully jump over to the pipes. In the corner here, we can spot a purple top hat… the Hidden Hat.

We now need to carry the Hidden Hat, all the way to the final boss in Chapter 18. If this sounds tedious, it is because it will be. You cannot fire guns while holding the Hidden Hat, so in combat you will need to leave it somewhere safe. This involves a lot of taxiing; get to a room, put the hat down, clear it, grab the hat, carry on. Save often in case something goes wrong! Make frequent Manual Saves (I kept around 3-8 that I would make throughout each Chapter) on top of religiously making Quick Saves.


Achievement #9 – Mega Hertz: Kill 5 enemies with one Grenade.
With the Hidden Hat, climb through the vent in the reception room & begin making your way out of Sector C. After the elevator we enter collapses & we fall into some water. Swim out, & carry on a little ways further until we first encounter the sticky rope trap Barnacles. When we first find them, there will be 6 of them; do not use our Pistol to kill them!

Instead, carefully use the four nearby Barrels, & get by the Barnacles with them all still alive… & our Hidden Hat. If you get caught, reload. Once you are past, kill the ambushing Houndeye, & navigate to the upper level where we will need to turn the valve to override the temperature control.
Before we carry on after the doors have opened however, head down the hall behind us & we can spot a cowering Scientist at a dead end. Get them to follow you through the door, across the walkway, & into the next room. Kill a Zombie in our way, & the Scientist will unlock the nearby security checkpoint; the Frag Grenades will be in the weapons locker inside.

Leave the Hidden Hat here (make a Manual Save) & backtrack to where those 6 Barnacles were. Make a Quick Save here in case you fail. Now try throwing a Frag Grenade into the tongue of the center-right Barnacle. If the 5 Barnacles at the top are still alive, the blast should kill them all & unlock this Achievement.


Achievement #10 – Well-Done: Cook a Grenade for too long.
With that done, now simply prep a Grenade by holding down the throw button & just don’t let go. When it explodes in our hands, we will unlock the Achievement.

That is our last Achievement for this Chapter. Now carefully transport the Hidden Hat with us to the end Elevator through the Lower Canals.

For this Chapter, we will need to locate & save all four Security Guards & two Scientists; there are more than this amount, however all the others found on the Chapter will have scripted deaths & cannot be saved. Even if you are playing on Normal Difficulty, I recommend leaving our followers behind & clearing areas ourselves before taking them further; it is safer. We can also leave the Hidden Hat behind with our followers wherever we leave them; just be sure to Save often in case of unforeseen glitches.

Uncooperative Scientist: In the room that we turn off the electricity barring our way, we will find a Scientist; this Scientist is uncooperative & we cannot save them.

Security Guard #1: When we turn off the electricity, head over to the previous blocked area & jump through the window. Round the corner, & we will be in the reception area for the Developer Offices. From here, begin heading down the only hallway available to us & open a set of red double doors to enter the upper level of a warehouse bay area. Head across a walkway straight ahead of us & we can find a Security Guard locked behind a chain link fence enclosure.

His “buddy” that he mentions, will have become a Zombie & come up behind him. Quickly kill it before the Guard takes any damage. With that done, he will unlock the enclosure, & we can lead him back to the reception room; we can find the Shotgun in the stash he was guarding…

Be careful when escorting the Security Guard as new Zombies will bust out of some previously locked offices to attack us along the way back.

1. Chapters: 4
2. Achievements: 12/50
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Security Guard #2: Now that we are back at the reception room, jump through a window to the right of the locked red double doors ahead of us, into a flooded office room that is currently electrified. Carefully get over to the far end & climb through the open vent where we will eventually fall through to the opposite side of the doors.

Climb up a ladder into a new vent, & it will take us into a maintenance bay with a Turret. Quickly rush underneath the Turret & raise the platform to either shutoff the power or destroy it with our Crowbar.

We can now safely backtrack to collect our first Security Guard & the Hidden Hat. With that done, carry on through the maintenance bay up some stairs; we can find Security Guard #2 at the top of them in our way.


Achievement #11 – Permeable Infrastructure: Use the alternate path in Office Complex.
Leave the two Security Guards (& the Hidden Hat) behind where we found the second one, & enter through the red double doors ahead of us. After passing through two more sets of red double doors, we will enter a large office space & be ambushed by some Vortigaunts.

Once they are dealt with, enter into the room that is directly straight ahead from where we entered this office space from. In here, we can find a ladder leading up into the ceiling. Destroy the ceiling tiles blocking our way & climb up the ladder to then enter a nearby vent. Follow this vent along & we will enter an elevator shaft where our Achievement will unlock.

Do not progress! Backtrack instead & carry on through the Chapter as normal so we can collect the remaining Scientists & Security Guards!

Scientist #1: Return to the office space we were in previously. There is only one other exit to this office space, & that is another set of red double doors in the far left corner from where we enter. Instead of going through them, head down a hall on the right side of the room & around the corner where a lone Vortigaunt will portal in. From here, we can pass through a broken down door, kill two Zombies, & find a Barnacle hanging above a room blocked by an upright desk. Kill the Barnacle, & break down the desk to find two Scientists; only the woman will agree to come with us. Lead her back to our Security Guards & leave her there…

Uncooperative Scientist: Carry on through the red double doors out of the office area, & kill some more Vortigaunts that portal in. In the next room, we can find some stairs leading up with a Barnacle in our way; be sure to kill it.

On this level, we can enter into a first aid station with a Scientist in it, who tells us that soldiers have arrived; they will not want to follow us.

Security Guard #3: Head up the stairs now & we will find a Turret at the top that is protected by a glass cover. We need to destroy it by throwing a Grenade when the cover opens or by perilously shooting it! Once it is destroyed, we can ferry our followers & the Hidden Hat to this location to leave them…

Open the next set of double doors, kill a Zombie, & then two Vortigaunts that will portal in further ahead. Open another set of double doors & we will hit a crossroads; straight ahead to our right or down to our left to a lower level 2. Stay on this level & go right to have our next Security Guard rush around the corner to meet us; take him back to leave with the others.

Uncooperative Scientist: Carry on through the Office Complex now, past a cafeteria, & we will enter a large walk in freezer space. As soon as we enter, a female Scientist will rush around the corner being Zombies; even when we kill them, she will not follow us.

Security Guard #4 + Scientist #2: Head through the freezer & use the vents & a crane to navigate your way out of it. From where we exit, after a maintenance shaft with some Barnacles, we will drop down to a Security Guard looting a dead one with a male Scientist standing nearby. These are our final two; tell them to stay here for the moment.

Unlock the door close by to the cafeteria, & taxi our four other followers & the Hidden Hat to this point & leave them all here as well.


Achievement #12 – Our Brains & Your Brawn: Assemble all 6 of the possible Scientists & Guards at the end of Office Complex.
Continue up the stairs into the next room that will be overlooking the cafeteria. Clear it of Zombies & Vortigaunts, & when the area is safe, lead our six followers up to it. As soon as they all enter this room, we will unlock the Achievement.

They will all refuse to carry on, & to their credit, the jump to the elevator ladder is extremely difficult while holding the Hidden Hat. Save here, as dropping the Hat down the elevator shaft is a no go! To make the jump without losing the Hidden Hat, sprint at the ladder & turn side ways at the last moment so the Hat sticks out to the side instead of smashing into the ladder. Carefully navigate the shaft & enter into an elevator through its top with the Hidden Hat to complete the Chapter.

1. Chapters: 5, 6
2. Achievements: 17/50
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Achievement #13 – Digital Wizardry: Kill 10 enemies with a reprogrammed Sentry.
When the Chapter begins, we will need to break a fire emergency override for a blast door to continue. In the following room, we will find a Sentry Turret. Quickly get over & behind the Turret & pick it up, being careful not to have it rotate & shoot you. We can potentially kill 1-3 Headcrabs nearby with it until it runs out of ammo.

After going through a cafeteria with a Vortigaunt ambush, head down the stairs to find two more Sentries we can collect to kill some more enemies. Vortigaunts will ambush us here shortly giving us another 1-3 kills. This is the best location to farm kills for the Achievement if you want to Save/reload; while there are a few more Sentries through out the Chapter, typically they will be more nuisance then useful.

There are two more Sentries we can use over the other side of a yellow shelf with 3 Headcrabs that spawn nearby as well…


Achievement #14 – Kinetic Repulsion: Kill a Marine with their own Grenade.
Carry on to find a group of two surviving Scientists, proceed to the next room, & we will find another that gets gunned down by a HECU Soldier. Immediately make a Quick Save here & get the Soldiers attention. When they come up the stairs, get in behind cover & wait for them to throw a Frag Grenade at us. Pick the Grenade up & throw it back to ideally kill them & unlock the Achievement.

Depending on luck &/or the Difficulty you are playing on, this may take a couple tries.


Achievement #15 – Unified Coupling Theorem: Help the Barnacle & Headcrab find true love.
This is another Save scumming Achievement that is easiest done on this Chapter. After a firefight with some more HECU Soldiers, we will cross a broken bridge with some Barnacles above us. In the next hall, take a left at the fork past some Sentries into the next room.

Before carrying on to another firefight, jump onto the conveyor belt dead ahead of us & follow it down. Quickly dispatch the HECU Soldier in the limbo room, & keep heading further down the belt. The belt will take us into another room that has around 5 Headcrabs in it. Quickly get through the room to the next conveyor belt, & try luring at least one Headcrab to follow you along it.

Nearing the end of the conveyor belt, quickly get off it as it will end in a Barnacle. Once you have the Headcrab in this room, make a Quick Save & try positioning yourself to get the Headcrab to get caught by the Barnacle; do not Save while the Headcrab is caught, it needs to GET caught each time to count. For this Achievement, this needs to be done 10 times; after a Headcrab has been caught by a Barnacle tongue 10 times, the Achievement will unlock. The Barnacle tongue is the actual trigger to log the Achievement; you do not have to wait until it is consumed.


Achievement #16 – Calculated Trajectory: Kill 10 Airborne Headcrabs using the Shotgun.
Return to the room with the Headcrabs & make a Quick Save before dropping back in. Now focus in blasting the Headcrabs out of the air with the Shotgun. When they are all dead, reload the Save & keep scumming until we unlock the Achievement.

This can be done at any point in the game in any location with at least a single Headcrab & a couple rounds of Buckshot for the Shotgun…

That is the last we need to do on Chapter 5, complete the rest of the Chapter making sure to cart the Hidden Hat along with us.


Unfortunately, we will be unable to use the Rail Car as the Hidden Hat will just fly off it the moment we accelerate; we will have to walk the rails…

Be careful when cycling the airlocks to enter into Silo D, depending on where you place the Hidden Hat, it may disappear!


Achievement #17 – Remote Detonation: Kill a Barnacle with a Satchel.
Once we enter into the control room of Silo D, we will encounter the Tentacles (it is easiest to leave the Hidden Hat in this room as we will have to return here later). Pass into the next room & up a ladder past a Security Guard & we can find Satchel Charges on the shelf ahead of us.

Toss a Satchel into any Barnacle tongue we come across & detonate it to kill it as well as unlock our Achievement.

The .357 Magnum: After the insanely epic sequence where we clear the Tentacles with the rocket engine, climb down the central column of Silo D where the Tentacles were erupting from. At the bottom, we can find the .357 Magnum on a ledge just above the water.

Now that we have it, really focus on killing any HECU Soldiers we come across with Headshots to unlock the Grey Matter Propulsion Achievement.

Trip Mines: Near the end of the Chapter, after we use a pulley system to move a large rusty pipe over for us to cross, we will shortly fall down into a storage room while walking through the pipe. In here, we can find a bunch of Trip Mines on a shelf; we need to kill 10 enemies with these for the One Step Ahead Achievement.

1. Chapters: 5, 6, 7, 8, 9, 10, 11
2. Achievements: 20/50
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Achievement #18 – One Step Ahead: Kill 10 enemies with Trip Mines.
This is a very easy Achievement to farm since any enemy types count towards it. Throughout the Chapter, keep an eye open for a good group of Headcrabs or lone enemy & make a Quick Save. Then deploy the Trip Mine, kill them, & reload the Save until the Achievement unlocks.

I farmed a bunch of Headcrabs at the bottom of a drop after a corridor full of Vortigaunts ambush us… Even if you walk through your own Trip Mine, so long as enemies die because of the explosion, it will count…


Achievement #19 – Grey Matter Propulsion: Headshot 20 enemies with the .357 Magnum.
This Achievement can be chipped away at over the course of the game or farmed when you find an easy group of HECU Soldiers to kill. I ended up farming this in our second encounter with the HECU where a Red Beret Soldier is with two other HECU Soldiers; you can carry on as well to find more HECU to farm.

That is all to do on this Chapter, get the power flipped back on & return to the room with the Gargantua. Get back to the far ladder, flip the turned off switches, & vaporize the Gargantua with the Static Discharge to progress out of Chapter 7. You will need to use the Rail Car to progress; just be sure you are taxiing the Hidden Hat along with you!

There are no Achievements we need to unlock on this Chapter. Simply get to the end with the Hidden Hat.



Achievement #20 – Dead Reckoning: Kill an Assassin with the .357 Magnum.
This is the only Achievement we need to worry about on this Chapter. Navigate through near the end of the Chapter when you take a utility elevator after passing through the cryo-freezers. At the top, we will see a Security Guard get sniped in front of us when they try to pass off a message; this is our first encounter with the Black Ops Assassins.

If you are out of Magnum rounds, quickly get to the upper floor of the hangar bay & enter into the office room at the top where we can get a full reload of it. Make a Quick Save here & use these Assassins to unlock this Achievement.

Captured: After we fight the Assassins & carry on, we will become incapacitated by some lucky HECU Soldiers who will take us prisoner; you must have the Hidden Hat in your hands when this happens or we will lose it!

Re-Collecting the Hidden Hat: When we come to, we will be in a trash compactor. Conveniently, we can see the Hidden Hat resting on a walkway just above us; be sure to collect it before carrying on!

There are no Achievements or notable events in this Chapter; take the Hidden Hat with you to the end. This is very platformer heavy Chapter & is quite irritating to pack the hat along with us… Take it slow, & Save often.


Questionable Experiment #1 – Alien Grunt: For the Ethically Questionable Achievement, we need to perform 5 different morally grey experiments when we come across them.

We can find our first when we first begin this Chapter. In this room, the A08-EHT Chamber, we can find an Alien Grunt locked in a containment cell. Get over to the control room & kill it with either poison gas, fire, or electricity.

Questionable Experiment #2 – Snarks: Crawl under the blast door & head up the hallway to the next area. Ahead of us, we can find the A07-Minor Xenos room. Enter it, & continue to launch Snarks out of the Snark Cannon until it runs out of “ammo”.

Questionable Experiment #3 – Bullsquid: This next experiment is potentially missable so be careful! Carry on into room A04-Mirco Optronic Necropsy & go to the control room inside. Release the Bullsquid from its cell & wait for it to walk towards the center of the room. Now press the big red “Push to Fire” button on the nearby wall to kill it with a tesla discharge.

Killing the Bullsquid any other way will void the experiment & the Achievement!

The Pizza Box: Pass through the large Men’s Changeroom & we will enter into the cafeteria room. On the front counter of the concession, we can find an open box of pepperoni pizza. Are your hands full with the Hidden Hat? Guess what? For the Pepperoni Precipitation Achievement… we need to carry this Pizza Box all the way to the final boss’s chamber as well. Yeah… not my idea.

There are two ways we can approach this. Make a Manual Save here, deal with the Hidden Hat first & beat the game, then reload back to this point & deal with the Pizza Box. Or, you can be a masochist like me, & we will juggle these two objects across every room for the rest of the game. If you decide to take both with you… Save often!... this is kind of a nightmare.

The best strategy for doubling down is just to leap frog the items. Lead with the Pizza Box until you get either a tricky spot or a good new “checkpoint”. Go back for the Hidden Hat & bring it forward to stash. Rinse & repeat. The Pizza Box is much easier to handle as it does not roll; wherever you stash the Hidden Hat, be sure it is somewhere safe & does not roll away or off a ledge.

Save often & don’t be afraid to leave both items behind when you think you will return to the room later on. It is also important to note that the Hidden Hat floats in water while the Pizza Box will sink! Check out my briefing for these Items in my Introduction for more information…

1. Chapters: 11, 12
2. Achievements: 26/50
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Questionable Experiment #4 – Headcrabs: When we reach the large atrium room, carry on into the next set of hallways & over to Lab B. Past room B04-Cryonics, we will find a disturbing surgery room that is locked to us. Head around the corner, & take a right down a hall with a fire exit sign pointing to it. As we continue on, we can see into a terrarium that is full of Headcrabs; enter the B08-CES Chamber Observation Area.

On the counter near a sink, we can find a yellow canister of Compressed Cyanogen Chloride. Pick it up & place it into the Experimental Gas Feed near the observation window; push the initiate button to kill all the Headcrabs with the gas.

This is foreshadowing…


Achievement #21 – Universal Gravitation: Get killed by your own Snarks.
In this same room, we can collect 5 Snarks. Make a Quick Save, & then throw down all of your Snarks so that they begin attacking you; when they kill you the Achievement will unlock.
If your Health is too high, just hold onto them until for later for when you take more damage or blow a few Grenades up in your hands.

We also need to kill 10 enemies using Snarks as well for a different Achievement…

Questionable Experiment #5 – Primary Laser: Head up to Lab D now & fight off some HECU Soldiers & Bullsquid. Enter into D07-Primary Laser, & we can spot a massive particle cannon. For the final Experiment, we need to shoot the Primary Laser at the kenneled Headcrabs in front of it. To do this, we need to power up Aux 1-4. Locate each of the four Aux rooms & press the “Laser Fire” buttons to engage them. We can find the Tau Cannon in Aux Room 2, be sure to collect it!

When all four have been pressed, return to the Primary Laser. Before firing it, be sure that the blast shield control is plugged in (in case you walked up & unplugged it) & press the “Test Fire” button to vaporize the Headcrabs.

If you remove the plug on the wall that controls the shield afterwards, we can use the Primary Laser to blast a hole in the wall to continue… Removing the plug before vaporizing the Headcrabs will open the path forward, but it will void our Achievement!


Achievement #22 – Ethically Questionable: Conduct all 5 of the questionable research experiments.
Missable. We will unlock this Achievement after completing the final Experiment. Since there are a lot of factors involved to this Achievement, there is a lot of room for error. If the Achievement did not unlock, return to the different Experiments & try again; only the Bullsquid experiment can actually be failed if you kill it in another way.


Achievement #23 – Quantum Capacitance: Overcharge it anyway.
With the Tau Cannon we find in Aux Room 2, make a Quick Save. Now hold down the charging ability of the Cannon until it backfires after a few seconds. This will injury us, but also unlock the Achievement.


Achievement #24 – Futile Resistance: Kill 10 enemies with Snarks.
With our Snarks, find a good enemy to farm on this Chapter; crawling Zombies are the easiest. Once we find one, & still have at least 2 Snarks left, make a Quick Save & farm that enemy to unlock the Achievement.

We will have more opportunities to collect/use Snarks in other Chapters…


The Mesa Cliffs: After progressing quite aways along the outside reaches of Black Mesa, we will have to cross a mine field & pass through a culvert to reach the mesa cliffs. If you are carting both Items around with you… this is a very difficult spot. Make a Save!

Do a dry run of sections along the cliff beforehand so you know where to go. Then carefully drop the Pizza Box down to the bottom ledge; we cannot drop the Hidden Hat as it will roll off the cliff, it has to be manually taken down by us. Patience is key…


Achievement #25 – Centripetal Attraction: Kill 20 enemies with the Hivehand.
After taxiing our Items off of the cliffs & through an obscene room sequence rigged with bombs, we will leap onto a utility elevator with a dead Alien Grunt on it where we can loot the Hive Hand. We will not need to Save Scum this Achievement; just simply use it as much as you can throughout the Chapter & it should unlock for you at some point.

It has unlimited ammo & there are quite a few enemies during this Chapter…


Achievement #26 – Stealth Technology: Escape the hangar in Surface Tension without alerting the Soldiers.
Missable. Once we painstakingly inch our way to the end of the Chapter, we will come across a lone Security Guard just before we enter hangar bay 7. Be sure to make a Manual Save here in case we mess up what is to come; leave behind the Hidden Hat & the Pizza Box too until we unlock the Achievement.

When the Security Guard opens up the door, crouch & stay behind him as close as possible. Follow in behind him along the walkways & never stand up or get ahead of him. Things are pretty straight forward until you reach the bottom of the stairs; the stretch from here to the door is tricky & you will frequently get seen.

Just before the Guard gets up to run towards the door, quickly sprint ahead of him & Crouch in front of the door/control panel to open it; do not hide behind the large wooden crate close by because they can detect you through it! If the stairs aligned, & the Security Guard opened the door without the Soldiers becoming alerted, we will unlock this Achievement after stepping through the door.

This will probably take you quite a few tries… When you have the Achievement, reload your Save back at our Items & ferry them forwards now; you will most likely have to kill the Soldiers.

You will want to make sure you have as high of health/shields as physically possible for the end of this Chapter!

Gargantua Chase: Near the end of the Chapter, we will get chased by a Gargantua. This is extremely difficult. We need to ferry one Item all the way to the end of the tunnel, then throw it through the open blast doors to the outside. Then we need to turn around & sprint back to collect the second Item we left; this is why we need such high health to evade the Gargantua.

Once both Items are outside, we can exit ourselves to kill the Gargantua with the Airstrike; the tunnel collapses behind it when the Gargantua exits so we must ferry the Items through this way.

If you do not have the health for it & cannot reload further back to get more, this could be the first breaking point. You will need to make a Manual Save here, never Save over it, & continue on with one of the two Items; when we beat the game, reload to this point & re-beat it with the other Item…

1. Chapters: 13, 14
2. Achievements: 30/50
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There are no Achievements to earn on this Chapter. Just focus on transporting our Items to the end…



Achievement #27 – Premature Expulsion: Use an entire clip of Gluon ammo in one continuous shot.
After we make our way into the Lambda Complex, we will eventually link up with some Scientists inside. When we find the second Scientist here, he will give us the Gluon Gun; collect it & make a Quick Save. Now simply fire it continuously & waste all of its ammo to unlock this Achievement.


Achievement #28 – Hyper Saturation Conundrum: Drown in Lambda Core's coolant.
When we take the elevator down to the Lambda Core, we can peer over the edge down below to see a pool of blue coolant. Make a Quick Save & leap over the edge into the pool. Drown yourself in the coolant to unlock the Achievement.

The Reactor Portals: After raising the coolant levels & flooding the reactor, we are able to swim through to the next area. Eventually, we will reach a massive silo with the Lambda reactor… This is probably the most annoying part in the whole game for juggling our Items through. We will need to take our Items one by one through a set of portals, taking us up the reactor. You need to time when you pass through a portal so that you land on top of the rotors. Your Item also needs to pass through the portal first or else it will stay behind. Make a Manual Save at the beginning & Quick Save often as you head up the reactor.

When you land on the first set of rotors, wait for the portal marked 02 in the reactor’s center to leap over to. Look up behind us & we can see where we will exit out onto the next set of rotors. We now need to time passing our Item & ourselves through to land on the next rotors; this is extremely difficult. I recommend doing the Pizza Box before the Hidden Hat is it is a bit easier; for the hat, try having it stand up on its base or head so it doesn’t roll.

Next you need to pass through the 04 reactor portal. When you get to the final level, pass your first Item through the 07 reactor portal to take it to the final room; do not enter it yourself!

Instead, leap back onto the rotors & pass through the 08 reactor portal to be taken aaaaallll the way back to the very beginning… time to do this all over again with our second Item. This took me 1.5 hours to get both Items to the top.

For a video to give you a visual guide to this, J4miboy has a good tutorial… it’s still insanely difficult to pull off.
https://youtu.be/WlvwobOenVc
Once you are in, we have one more challenge to do. Leave the Items where we came through, Saving obviously, & make your way around the core to remove the two containment locks. With that done, we will open a final reactor portal in the center of the room. Ferry both Items through, & pass through yourself to be done this horrific task.


Achievement #29 – Xen When: Wait too long to jump into the Lambda Teleporter.
Once we have linked up with Lambda Team, we will be able to re-equip ourselves as well as obtain the Boost.
When we enter the Lambda Teleporter chamber, we will have to fight off waves of Aliens before the teleporter is ready. After it is, & the Scientists tells you to go, do not enter the portal & instead keep holding out. We need to hold out for a minute, which can actually be pretty tricky. If need be, just sprint around the room dodging the enemies until the teleporter overloads & our Achievement is unlocked.

It is actually easiest to hide right off that bat & not even engage the first three Alien Controllers that arrive; more enemies spawn when others are killed.


Achievement #30 – Rare Specimen: Send the Hidden Hat to Xen.
When the Lambda Teleporter is ready, & we have the previous Achievement unlocked, quickly toss the Pizza Box & the Hidden Hat into the Teleporter. We will unlock this Achievement when the Hat hits the Teleporter.

You know you will have done everything right because we will actually see both the Pizza Box & the Hidden Hat in a cut scene as we are warped to Xen; if you see one & not the other, or neither, you need to reload & try again.

1. Chapters: 15
2. Protozoans: 11/64
3. Achievements: 33/50
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When we arrive in Xen, the Hidden Hat & Pizza Box will be no where to be found. Do not worry, they have been teleported further into the Chapter in a specific location for us to find; we will get a brief few minutes of peace without having to worry about them for now.

Starting in this Chapter onwards, things will slow down even more though however as we now need to hunt down & kill 64 Protozoans; there are 37 of them to find on this Chapter.


Achievement #31 – Orbital Trajectory: Skip the opening Xen island with a secret jump.
From where we arrive in Xen, take the path ahead of us up to the islands edge & make a Manual Save here. Instead of taking the path off our left, like we are supposed to, take the path to the right & we will find another edge to the island. In front of us here, we can see some floating rocks. Drop down to the floating rock right below us first; we can just do a regular leap to it. Now use our Boost to get to a rock across from us to the right. From here, look down to our right to spot a large flat rock close to the cliff wall to get to next.

While on the flat rock, look off our right again to spot a shining blue post on the ledge of the next island. Carefully Boost across to it, holding down our Boost to reach it, & we will unlock this Achievement.

Protozoan #1: Reload our Save to get back to the first island, & start heading down the pathway to our left. When we enter the cave ahead, we can see a floating amoeba blob; destroy it!

Protozoan #2: Our next Protozoan can be found shortly after we exit this cave on the other side. Head down the path ahead & we can find it floating off the edge to our right.

Protozoan #3: Carry on across the island & leap down to the second one where we had skipped to previously. Before we lower the bridge, look down below it in the pool of water to spot another Protozoan hovering there.

Protozoan #4-5: Leave this island, & boost across the next one that has flowing blue healing water going down it until you reach a rock archway with where a group of Houndeyes will ambush us. Look off our right before passing under the arch to find two Protozoans hovering at a dead end.

The Hidden Hat & Pizza Box: Were you enjoying not packing something around with you? Well… it was short lived. Carry on across the islands & through a portal. Follow the path along past some weird hanging growths that will electrocute us & get to the end. Before we enter into the nearby cave, look across the way from it to spot a lone ledge with an orange crystal on it.

Boost over to it & we can find our long lost Pizza Box & Hidden Hat tucked inside a small alcove. Sanity was nice while we had it… This is potentially another place to break our playthrough down if you wanted. Make a Manual Save to not save over, & carry on to the end of the game from here one Item at a time. If you are still crazy like I am, you can get back to the grind of taxiing these Items across all of Xen… It is possible to get them all the way to the middle of Chapter 17!


Achievement #32 – Nuclear Fishin’: Kill an Icthyosaur with either the Tau or Gluon.
Enter into the cave now & it will expand into large flooded section, make a Quick Save here. Standing above the water, we can see a few Icthyosaurs swimming around in the water; pull out the Gluon Gun or the Tau Cannon & try sniping them to unlock this Achievement.


Achievement #33 – Following the Rules: Use the welcome mat.
Restore power to the front entrance & enter into the Lambda field base up ahead. Before carrying on, stop immediately in the entry way & look down at the next door to see a welcome mat in front of it. Crouch on top of the mat & interact with it to unlock this Achievement.

Cyanogen Tank: Make your way through the field base until you reach the room where we need to power up a door. Pass through the door into the next room & we can spot a yellow canister of Compressed Cyanogen Chloride. You want to know what is worse than taxiing two Items… taxiing three Items.

Unfortunately, I am not joking, we now need to pack this Cyanogen Tank with us, but only until the next Chapter. We need this Item to defeat one of the two bosses in Xen as well as for getting to Protozoan #59.

Protozoan #6-7: Get out of the field base now & make your way over to some exploding masses. Destroy them, & use a crystal to power up a door across the way from us on a scaffold. Enter through the door to find a very beautiful pool with a large tree growing in the center of the area.

Directly across from where we enter, we can spot two Protozoans floating above the water near a strange creature that looks like a Tentacle.

Protozoan #8: To progress through this area, we need to get up on the leaves above the baby Tentacle & make our way along a tree root to the right. At the top, three Houndeyes will charge at us; we can find a Protozoan here at the top underneath a tree root that will be above us, it is just before you approach the next baby Tentacle.

Protozoan #9-11: Past the baby Tentacle now, enter into the passage to our right with two Bullsquid in it. Carry on down until we pop back out near the lake we were at previously. Look off our right out here & we can spot three Protozoans hovering above the water.

1. Chapters: 15
2. Protozoans: 34/64
3. Achievements: 33/50
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The Abyss Jump: Make your way out of the lake area into a new cave that will have a long red pulsing tube in it. Shoot a nearby… thing, & the tube will turn blue, opening a leaf for us to Boost to. The problem is, is that when we jump over we cannot get back across to collect our other Items.

If you want to persevere & jury rig getting the Items across, it is actually possible albeit tricky; before doing anything, make a Manual Save here. If you cannot, do not fret, as there is a way we can backtrack to the Items to bring across the gap.

To get the Hidden Hat across, the best way I found is to Shotgun-punt it (alternatively the Magnum also works better if you have the ammo). Stand at the edge, equip your Shotgun, pick up the Hidden Hat & aim up towards the ceiling. Do some test throws; you want to aim as high as you can without it bouncing off the ceiling. Once you have found the sweet spot, make a Quick Save, & throw the Hat to shoot out of mid air with the Shotgun. This is hard, the moment you throw the Hat, you need to aim slightly down to hit it the Hat out of the air. You will want to do this as fast as you can to hit the Hat while its arc is still high. A lot can go wrong with this, it takes the perfect shot to even hit that Hat, then you have to be lucky to have the Hat land in such a way that it does not roll off the leaf. It took me around 30 tries to get the Hat successfully onto the leaf.

The Shotgun-punt will not work for the Pizza Box. The best way I found for it, quite easily actually, was to use Satchel Charges. Lay down the Pizza Box at the edge & have either the bottom or the lid facing you so there is a full flat surface to catch the explosion. Don’t have the box on its side or upside down. With that, throw a Satchel Charge down off to the side, & manually pick it up to place in behind the Pizza Box; you can put two there for good measure. Be sure the Pizza Box is directly facing the leaf & that the Satchel Charge is right behind it. If done correctly, blow the Satchel Charge & it will launch the Pizza Box straight across the abyss onto the leaf.

Lastly, the only way to get the Cyanogen Tank across is just to manually jump it across; it is way too heavy to punt across.

Alternatively, & probably less of a headache overall, we can actually backtrack to this point & do large circuits to get our Items across. I will cover this bit after the next Protozoan entry…

Protozoan #12-14: Regardless of how you get across, drop down through the gap in the cave & we will exit outside into a new area. Immediately where we exit, look off to your right to spot three more Protozoans.

The Item Circuit: After we kill two waves of Suicide Houndeyes, we can find a waterfall off our left where the river flows. If you look down below it, you will see it leads down to where we entered that beautiful area with the large tree above it. Drop down, & backtrack all the way to where our other two Items are; rinse & repeat to bring them all forward. Extremely tedious, but very effective.

Protozoan #15-17: Follow the river down the opposite way now & it will end in another one of those red pulsing tubes. Follow the tube along to the right through the water, & we will enter a small cave. Look up above us once inside to spot three Protozoans hovering just above us where the growth we need to shoot is.

Protozoan #18-25: Power up a portal & send the Items through one by one before entering through yourself. Activate a bunch of blue tubes to reveal a path forward & do a mini-circuit getting our Items over a new smaller gap. Then we must destroy four growths to power up for tubes to open some leaves so that we can progress.

When we have completed that, pass through the next tunnel ahead to then see a whole (Censored by Steam) ton of Protozoan. Eight to be exact, all hovering over the area we will need to Boost to next.

Protozoan #26: Carry on down a river & we will encounter a Houndeye Bull annihilate a Bullsquid. Keep going on further, down a corridor with some baby Tentacles in it, to find another Houndeye Bull with some smaller Houndeyes. When they are dead, look off our right to find a floating rock close by; a Protozoan will be hovering above it, it can be a bit tricky to spot against the sky.

Protozoan #27: From here, follow the ledge along & take your first left down a tunnel where some more Houndeyes will ambush us. Head to the end of the tunnel & we can snipe another Protozoan. Once again, this one is super tricky to spot as it blends in with the sky… space. For me, it was floating in space to the left of the Boids flying around in circles.

Protozoan #28-30: Follow a river along onwards, through some portals, & through a flooded cave. When we exit, we will need to Boost our way up a small cliff & over towards a leaf on some roots to continue. From up here, we can spot three Protozoans dead ahead of us.

Protozoan #31-34: Follow this next river downwards & drop through a hole into a large pool below; we can find four Protozoans hovering over the pool here.

1. Chapters: 15, 16
2. Protozoans: 46/64
3. Missing Research Team: 3/7
4. Achievements: 34/50
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Protozoan #35: Pass through the cavern ahead & we will exit back outside. Leap across three large lily pads to get to a small bank with a HEV Suit corpse on it. Before carrying on, look down into the water towards where we need to go to find a lone Protozoan swimming.

Protozoan #36: Make your way out to the edge of the island we are on & we can spot a strange island off in the distance. Drop down a few ledges, & pass through another flooded cave until we reach another outside area with roots leading all the way to the strange island. From where we drop down, we can see two different roots we can step onto. Go to the small root off our right, then look down through a hole into space off our left to find a floating Protozoan hovering over the abyss.

Protozoan #37: For the final Protozoan of the Chapter, look directly above where we are to see a root heading back towards the cliff wall we came down. Navigate along the roots up to it & we will enter a small cave with a Bullsquid in it; the Protozoan will be at the back.

When we enter the new island, we will need to get a massive portal ready to continue. Leave our Items behind in the main control room while we get it ready; we can get back to them before jumping through the portal.

In this Chapter we will need to kill 22 more Protozoans as well as find the 7 missing Scientists in this Chapter for the Post-Mortem Interval Achievement.


Achievement #34 – Gonad Glider: Get whacked into oblivion in the ledge fight.
Shortly in this Chapter, we will enter a massive outdoor arena that looks like a boss room… you’ll know it when you see it. Stash your Items somewhere safe, & interact with three glowing orange crystals to begin the fight with Gonarch. Make a Manual Save before activating the final crystal!

For this Achievement, we need Gonarch to smash us out of the arena into open space & kill us. If I understand the Achievement right, it isn’t just getting knocked off the map from her… it’s getting knocked off by the specific attack where it cerslunks us with its dangling… dongle? Getting knocked off by its charge attack or its claws won’t count it seemed.

Protozoan #38-40: Drive off Gonarch using our Rocket Launcher, & it will escape through a tunnel. Pack our Items along with us until we reach a large web mass going up a slope; we will fall through this so toss our Items on top of it before we do. From where we drop down, look ahead of us to spot three Protozoans.

Protozoan #41: Detonate the wall ahead & pass through a tunnel to the other side where it will collapse behind us; another Protozoan will be in front of us here.

Sending the Cyanogen Away: In this room, we can find a small circular platform at the back right side. Place our Cyanogen Tank on top of it, then press the green button nearby to teleport it to the secret chamber; we will find it again later when we are going to kill Gonarch. One less Item to worry about packing now.

Doing this will unlock the secret chamber to us & let us snag Protozoan #59 as well.

Protozoan #42: In the room we encounter Gonarch in next, follow some wiring around a corner to our right & detonate another set of explosives. Pack your Items along with you & drop through some more webs to a lower down level. Head down a small passage & look out to our right across an abyss towards a waterfall where we can spot a Protozoan.

You may need to Shotgun-punt the Hidden Hat across the next gap, as it is difficult for us to return back to this ledge for our second Item.

Protozoan #43: Get away from Gonarch shooting at us again, & Boost across some rocks over to the side of the chasm he is on. As soon as we enter the next tunnel ahead, there will be a Protozoan right in front of us.

Research Team #1: We will find our first dead Scientist further down this tunnel as well. When we enter the room with the two Bullsquids & the survey device, take a left down a dead end tunnel to find the Scientist’s body in a HEV Suit; you need to actual interact with it for it to count.

Turning on Captioning – Closed Captions can help as it will tell us “Retinal Scanned Use” meaning that we did it.

Protozoan #44-46: Down in the next chamber there will be three more Bullsquids, a large pool of healing waters, & another three Protozoans.

Research Team #2: Carry on through the cavern & drop down to a lower section. Crawl through a small space into a room full of orange crystals; our Scientist will be in the left corner from where we enter. Be sure to interact with it.

The Gonarch Chase: This is another difficult sequence to keep our Items with us. To start, carefully drop your Items outside of the cave we are in; put the Pizza Box off to the side of the wall out of the way & take the Hidden Hat with us. When we enter into the small cave with all the Houndeyes, this will be a short safe spot; go back to collect the Pizza Box.

Drop the Items down off a ledge, & we will be in a large area with some purple crystals. This next part is tricky. Before detonating the explosives, bring our Items over to that lone flat rock in the water so they are not launched by the explosion. As soon as we detonate them, quickly ran & grab the Hidden Hat & Boost down the tunnel. Where we need to go is to the left, but if Gonarch corners us there, he will cave that area in & kill us unless we are inside that cave; that also blocks us in. Instead, run as far down as you can & try throwing the Hidden Hat into the cave before Gonarch can come. Then dodge her, & grab the Pizza Box to take in with you. This is very hard. Often times Gonarch will still chase you into the cave & crush you or smash you into a corner & just stun lock you.

Research Team #3: When you have managed to get yourself & both Items into the cave, exit the other side & move the Items just outside the cave. Now make your way into the large chamber & follow some wiring up some ledges to another detonator. Before you activate it, peep over the ledge beside it near an orange crystal to find a dead Scientist. Interact with it.

1. Chapters: 16
2. Protozoans: 59/64
3. Missing Research Team: 7/7
4. Achievements: 35/50
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Protozoan #47: Fortunately, when we push the detonator, a crystal will come down in the explosion & bonk Gonarch making her run away. We get a bit of a breather. Take our Items across the gap into a tunnel that will take us into an outer area flooded by toxic water. Look up above the water near the ceiling to spot a Protozoan.

Protozoan #48-51: Use the “lily pads” to get across the water to the far side & we can find a deep hole with some climbing ropes going down it. Jump over to a ledge across from it with some blue mushrooms on it, & look down into the pit to see four more Protozoans.

When we drop down the pit, throw the Pizza Box into the center of it but be sure to jump down holding the Hidden Hat as it is prone to disappearing here.

Research Team #4: Carry on a little ways & Gonarch will destroy an exit to the outside forcing us to head down a corridor full of blue crystals. Burn the webbing blocking our way, & head further down to see a dead Scientist stuck in some more webbing right in our way. Interact with it.

Research Team #5: This is going to be our hardest Scientist to find as it is found right at the start of another Gonarch chase. Navigate along for ways until we reach an outer chasm area with a waterfall flowing down into an abyss. Burn a set of webbing to continue & the area we enter next… will begin the chase. Carefully drop our Items into the area before continuing.

As soon as we drop down, Gonarch will drop into the room as well & a section of the wall to our left will give way. Not only is this a safe spot for us to hide our Items, but we can find a dead Scientist to interact with here as well.

The Gonarch Chase: Now for another hair pulling moment trying to get our Items out of this pickle. The first problem, is that once we drop down the small ledge ahead of us, we cannot get back to this safe zone. We need to quickly rush out & throw the Hidden Hat to the lower level & run back to the safe zone; praying that it won’t roll away or get knocked by Gonarch. Grab the Pizza Box now, & begin boosting your way down the tunnel until you reach a small cave entrance. Huck the Box inside & immediately turn around & get ready to dodge Gonarch to go back for the Hidden Hat. Dodge Gonarch a second time & get to the safety of the cave.

Accurate Boosting is essential for this as Gonarch can outrun us!

Protozoan #52-54: Once inside the cave, burn the webbing blocking us & burn another set of webbing over the floor to drop down through. After flooding a series of caves & swimming through them we will eventually have to destroy a large red crystal in the ceiling to smash through the floor. Further flood the massive chamber we have been in & swim up to the surface; look over near the top of the main chamber to find three Protozoans hovering near the back.

Protozoan #55-58: Keep navigating along & we will need to destroy a second red ceiling crystal to fully flood our massive chamber. Get past where we killed the previous Protozoans & head down the tunnel beyond to find four more of them in it.

Be careful without your Items in this tunnel as it is filled with slippery oil!

Research Team #6: When we drop down through the oil slide, Gonarch will bust through a wall in front of us. Immediately off our left, we can see some webbing with a dead Scientist in it. Interact with them.

The Gonarch Chase: Now for our final & one of the worst chase sequences with Gonarch. To continue, we need to light this whole area on fire. The trickiest part about this, is that there will be a bridge we cross that will catch on fire & break. This means we have to take one Item all the way down & throw it to the other side of the bridge & run all the way back to the other room, dodging Gonarch, to collect the other Item; the bridge will only break once we cross it. Once again… this part really sucks.

When you make it, sprint down the tunnel ahead with your other Item until you reach a Supply Pod. At the pod, turn immediately left & enter into a small tunnel; this is a safe zone. From here we can now go back & collect the other Item we threw across the bridge.

Protozoan #59: In this tunnel, we can find a Protozoan, this is our last Protozoan for this Chapter. This tunnel is only unlocked if we sent the Cyanogen Tank to the secret chamber.

The Cyanogen Room: At the end of the tunnel, we will finally be reunited with our Cyanogen Tank if we successfully brought it over from Chapter 15 & teleported it. Make a Manual Save in this room because there is going to be a lot that is going to happen. Do not interact with the tank just yet!

Research Team #7: First, we will locate our final Scientist. Look at the far upper left wall of Gonarch’s boss room & we can see some rock ledges. Carefully Boost across to them, there will be two, & we can find our final Scientist slumped on top of some twisted spiny stalks coming out of the wall. Inch your way to the edge & interact with it.


Achievement #35 – Post-Mortem Interval: Find each member of the 7 missing research teams.
If you have been following along with the guide, we will unlock this Achievement after interacting with the final Scientist. If the Achievement does not unlock, you may have forgotten to interact with one of the bodies or reloading a Save where you assumed you already had. Unfortunately, you will most likely have to restart this Chapter… but do not do so until you beat the game if you are packing Items!

1. Chapters: 16, 17
2. Protozoans: 59/64
3. Achievements: 40/50
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Achievement #36 – The Plan: Use Cyanogen to kill Gonarch.
Missable. Now it is finally time to kill Gonarch; one of three ways that is. Reload our Manual Save, & approach the Cyanogen Tank. Pick it up & place it inside the receptacle close to a large white tank. Push the button & cyanogen chloride gas will fill the boss room & instantly kill Gonarch, unlocking our Achievement.


Achievement #37 – Unquestionably Ethical: Don't use the Cyanogen & let the Gonarch live.
For the next killing Gonarch Achievement, we will NOT be killing Gonarch. Reload the Manual Save & this time navigate along the ledges where we found the last Scientist off our left. Carry on from his corpse along two more upper ledges then boost into a cave in the far-left corner of the upper boss room. The Achievement will unlock once we drop down into it.


Achievement #38 – Doctor’s Signature: Deliver the finishing blow to Gonarch with your Crowbar.
Reload our Manual Save & now we must beat Gonarch the old fashioned way. Drop down & begin peppering her with Rockets & other high damage Weapons. After causing a certain amount of damage, the two of us will fall through the boss room to the next level. Weaken her a bit more before finishing her off with the Crowbar.

There is an Autosave that triggers as we fall down, but you can make Quick Saves as you whittle her down to make it easier… When she is weak, try using Weapons like the Magnum or Shotgun, so you can count how many shots it takes to kill her; then reload & stop one shot short to use the Crowbar.

Avoiding A Final Fight: Reload the Manual Save for the final time & now we have to make a decision on how we want to get out of here with our Hidden Hat & Pizza Box. Though difficult, it is possible to navigate our two Items across the upper ledges & escape without having to defeat Gonarch; if you are only doing one Item this run then this is a piece of cake. If you are doing two Items, it can be tricky getting back to the Cyanogen room for the second Item you need to taxi across. You need to time your jumps well to get back.

The Final Fight: If you cannot manage to get the jumps down to ferry the Items out of Gonarch's lair, then you must take them down into the fight with you to escape. The Pizza Box isn’t too bad, but it is the Hidden Hat that will cause the most grief.

Before dropping down to fight Gonarch, try sniping her from where the Cyanogen Tank is. Be as accurate as possible, & if you miss too often than reload & try again. Doing this, we can always stay one level above Gonarch & keep knocking her down while having our Items protected. When you throw the Pizza Box off the ledge, it typically gets stuck in the spikes below; you may have to use Grenades to blast it out. We definitely want to jump down holding the Hidden Hat so we can guarantee its safety.

Use up all your Rockets, Gluon energy, Crossbow Bolts, SMG Grenades, & Magnum rounds for the first phase, then try resorting to throwing Frag Grenades, Satchel Charges, & even Snarks at him for phase two. The Satchel Charges are especially useful for high damage if Gonarch is directly below you.

When you do not have a choice, & Gonarch has made it to the center of the room to bombard us. Carefully get the Items down safely behind one of the columns on the third level, restock on health & ammo, & finish her off.

Though we have finally made it to the second last Chapter… our struggles do not end, & in some cases will get harder. Keep in mind as we play this Chapter that we cannot kill a single Vortigaunt. For hostile Vortigaunts, we must evade them & locate the Controller that is indoctrinating them; kill the Controller & the Vortigaunts will become non-hostile. Vortigaunts can be killed by other enemies, so long as we were in no way directly related to it.

Getting Through It: Right off the bat, once we get passed the Tentacles, we will be faced with some floating plateaus we need to boost across. Halfway through, the gaps will become too big for us to go back for our left Item.

The best way to get through this, is to Shotgun-punt the Hidden Hat over to a ledge against the cliff in between two waterfalls then Boost over to it with the Pizza Box. From here, we can then use the nearby structure to make it the rest of the way over & back.

Vortigaunt Encounter #1: When we make it across & crawl through a cave, we will see some imprisoned Vortigaunts being beaten by two Alien Grunts. We cannot kill any of the Vortigaunts, deliberately or accidentally. Kill the Alien Grunts, then check around to make sure you can find all four of the Vortigaunts still alive/hiding.

Vortigaunt Encounter #2: Take the elevator up & we will enter into a village like area. There will be many friendly Vortigaunts here, be sure not to kill any.

When we reach the second activator for the portal device, make a Quick Save here as things are about to get intense.


Achievement #39 – Anti-Matter Over Mind: Kill a Controller without killing any of its mind-controlled Vortigaunt slaves.
When we press the second activator, four Controllers will spawn in & indoctrinate the nearby Vortigaunts; we cannot kill any of them! We must kill only the four Controllers, which is challenging. Kill one of the Controllers that is tied to a Vortigaunt, without killing the Vortigaunt, to unlock the Achievement.


Achievement #40 – Contest Propellant: Find the snack supply canister.
After the Controllers are dead, we can leave the Vortigaunt village through a vent. Before we enter the elevator though, look to your left & push aside two large crates to enter into a side room. Head up to the second level & we can find a supply canister that will explode with off brand snacks when we approach it, unlocking the Achievement.

When we take the elevator out of the village, check your in game Achievements Tab & look at the PhD In Pacifism Achievement. If it says 1/7 complete, you were successful.

1. Chapters: 17
2. Protozoans: 59/64
3. Achievements: 43/50
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Achievement #41 – Black Mesa Decathlon Winner: Escape the Gargantua’s Lair without taking any damage from Gargantuas.
Missable. Take the elevator out of the village now & we will begin making our way up a murky river towards a dam. When you get your Items on top of the dam, make a Manual Save here & do not Save anymore until we unlock this Achievement! Saving at any point once we pass the Loading Screen mid way up the river will void the Achievement. If you can time it right, you can make a Save further up the river closer to the Loading Screen, but it cannot be after it.

Leave our Items behind for now as we will worry about them after we unlock this Achievement. When we drop into the area beyond, we will land in a Gargantua COLONY. We need to get out of this area without taking a single point of damage from them.

If done right, we will unlock the Achievement after we have to Boost across a very large gap over to a waterfall. When we turn around, we will see all the Gargantuas gathered on the opposite side very pissed; its actually a pretty cool scene.

What unlocks the Achievement is never reloading your game after seeing that initial Loading Screen. Anytime you restart, it must before the Loading Screen. You can pick up health/shields, you can take damage from other Aliens (Houndeyes, Bullsquid, etc.), your game can make Autosaves still, but you cannot take damage from Gargantua or reload your game after that Loading Screen has occurred. That is what voids it.

The Choice: Return back to our Manual Save at the dam, & we can bring forward our Items to the top of the entrance to the Gargantua lair. Here, we will need to make a decision: only one Item can come with us to the end of the game. While it is technically possible to get them past the Gargantua lair, we will be stopped immediately afterwards by vents that will only suck us up & what we hold; throwing an Item into it will not work.

Note that these vents are terrible for transporting the Pizza Box; 9/10 times it will get caught. Always Save before entering one, & be extra patient with the process.

Make a Manual Save here, do not Save over it, take either the Hidden Hat or the Pizza Box, & let us soldier on.

Vortigaunt Encounter #3: Our next Vortigaunt encounter will be when we reach a massive power generator system within a cave system. There are many Vortigaunts around here so be careful.

After we cause the final generators to go haywire, some Controllers will portal in & make our lives difficult. Get yourself to as safe of a position as possible, away from Vortigaunts, & take out the Controllers.

Getting past the encounter & exiting the cave will give us a 2/7 complete for the Achievement.

Vortigaunt Encounter #4: The next chamber we encounter Vortigaunt in will be an Alien Grunt breeding lab. Once again, when we cause the system here to go haywire, more Controllers will arrive that we will need to carefully defeat.

Red Laser Section #1: When we navigate out of the lab to the next upper level, we will enter a vent. At the end of the vent, when we look down, we will see a room full of red lasers firing below us. Make a Quick Save here! For the Laser Immunization Achievement, we cannot get hit once by a single laser this entire Chapter. If you get hit, reload your Saves immediately.

Fully escape the Alien Grunt lab to complete 3/7 for the Achievement.

Vortigaunt Encounter #5: In the next area, we will need to get past an army of portalling Alien Grunts. When we get to the upper level, we will find some more Vortigaunts.

Escaping this area through the Alien Grunt meat grinder will give us a 4/7.

Vortigaunt Encounter #6: Our next encounter with Vortigaunts will be in a large conveyor belt line full of Alien Grunt pods.

Red Laser Section #2: When we get through the lower level of the facility, we will pass through a vent & enter an inner pod line. We will need to stand on one of the pods as it arrives & evade the red lasers that are brought into our path; make a Quick Save before attempting.

Red Laser Section #3: Eventually we will reach another inner pod line & need to stand on a pod to get through. We will be detected however, & our pod will be taken to a decontamination room instead. We will need to dodge the lasers as they come at us, Quick Save often.

Completing up to this point with no Vortigaunt deaths will give us a 5/7 complete.

Vortigaunt Encounter #7: When we reach the next half of the conveyor belt assembly line, we will now have to worry about Controllers. Be extremely careful as the Alien Grunt pods can explode by us & potentially kill Vortigaunts! Take it slow & aim true.

Getting past this area successfully will give us 6/7 complete for the Achievement; one section left!

Vortigaunt Encounter #8: Our final stretch of encounters take place along the upper reaches of the assembly line. We will need to go straight up.

Red Laser Section #4-6: To progress onwards, we will need to disable some force fields blocking our way. To do this, we will need to fall down shielded holes that have red lasers spinning around them. Always Quick Save before attempting each one.

One of these paths is filled with Vortigaunts that will become indoctrinated; we will take a lot of damage, but exclusively attack the Controller & its invulnerability crystals!


Achievement #42 – PhD In Pacifism: Don't kill any Vortigaunts in the Borderworld.
Missable. Once we finally exit the Alien Grunt assembly line, we will launch ourselves out to a new area. Once we get encased in a square force field, the Achievement will unlock if we personally had not killed any Vortigaunts.

If it does not unlock, then you must have killed one along the way & will have to restart. Fortunately, we will have to do a second run of this entire base again anyways with our last Item…


Achievement #43 – Laser Immunization: Complete Interloper without taking any laser damage.
Missable. If done correctly, we will unlock this Achievement as soon as we hit the final jump pad taking us up to the next level as well. If it doesn’t, it means you were hit by a laser somewhere & will have to do the base run again.

This is a very fussy Achievement, & it took me a few runs after beating the game to unlock this… Unfortunately, this has to be one of our most tedious Chapters to have to redo…

1. Chapters: 17, 18, 19
2. Protozoans: 64/64
3. Achievements: 50/50
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The Tower: We now need to carefully get our chosen Item up the Controller tower. We will be constantly fighting waves & waves of Controllers heading up to the top of a tower. Keeping our Item safe is paramount; always put your Item against one of the walls around the elevator. These walls swap out, so be sure to move your Item in behind a new one when this happens.

Near the top of the tower, there will be a very difficult fight with four invulnerable Controllers. To keep our Item safe, try stashing it in one of the four walled areas we need to enter to take down the Controllers shields. Carefully destroy the first one, then tuck the Item behind its walls to be stress free.

For the final section on the elevator, there will be no walls to hide our Item behind. Instead, we will need to pin our Item to the elevator column behind us & always keep your eyes on it. To make the elevator go again, you need to kill at least 5-6 Controllers. Kill some Controllers & check to make sure your Item is still there. The moment the elevator starts moving again, run to pick the Item up.

Protozoan #60-64: After we escape up the rest of the tower, we will enter a cave system. Navigate through it until you see a room with blue energy containment fields around human objects. Be sure to loot the ammo in some of them & take a vent out of the room. You will see a Pizza Box in one of the tubes; it is not YOUR Pizza Box, & unfortunately cannot be extracted from the tube… I tried.

When we exit vents, we will be in a large room with our final five Protozoans in it.


Achievement #44 – Prolific Popper: Kill all 64 Protozoans in the Borderworld.
If you have been following along with the guide, this Achievement will unlock after killing the final Protozoan. If it doesn’t, then it means you have unfortunately missed some along the way & will have to re-run Chapter 15 up to this point…

Before we enter the massive portal to Nihilanth (you’ll know it when you see it), make a Manual Save! Be sure to throw your chosen Item through the portal as well before you go! It will not appear on the other side; you just have to trust you succeeded & you will find out in Endgame.



Achievement #45 – Specimen GG: Take out all three Healing Crystals in Nihilanth’s Chamber at the same time.
The two Achievements with regarding Nihilanth take a bit of fore planning & speed. As soon as we enter through the portal, we need place at 2 Satchel Charges on each of the three orange rings that circle Nihilanth; they are not far away from his radiation circle. If you run out of Charges, start destroying a shield generator above him to get some Supply Pods to arrive.

When you have at least 2 Charges on each of the rings, go & quickly destroy the three shield generators powering Nihilanth & then begin attacking him. When he takes enough damage, he will summon his Healing Crystals; swap back to our Satchel Charges & detonate them all at once to unlock the Achievement.


Achievement #46 – Late For Work: Defeat Nihilanth in under 4 minutes.
With that done, switch to the Gluon Gun & begin hammering Nihilanth. Standing near the Supply Pods can make reloading much faster. Keep whittling his health down until his head opens up & reveals an orange crystal. Hit the crystal to perform the finishing blow on Nihilanth; if you did this in under 4 minutes, we will unlock this Achievement as well.



Achievement #47 – The Rarest Specimen: Carry the Hidden Hat to Endgame.
If chose to take the Hidden Hat through the rest of the game & tossed it through Nihilanth’s portal, we will spot it on top of G-Man’s head when he arrives at the end of the game. This will unlock our hard earned Achievement… all of that pain… for this.


Achievement #48 – Rather An Anticlimax: Decline G-Man’s offer of employment.
Story Related. When we appear on the train with G-Man, he will open a portal for us to enter. For this Achievement, do not step through the portal, & instead stand there for 20 seconds to unlock the Achievement & face an unwinnable battle.

With this done, reload your previous Manual Save way back when you made your decision about the Items above the Gargantua lair, & go to take the next one through Interloper to Endgame.


Achievement #49 – Pepperoni Precipitation: View the *other* Secret Ending.
Identical to the Hidden Hat, we must take the Pizza Box all the way to Endgame & throw it into Nihilanth’s portal. The Pizza Box is a bit more frustrating in Interloper I found as it would constantly get stuck in the vents. Stick with it, & we will unlock this Achievement after killing Nihilanth & G-Man shows up… in a rain of heavenly pepperoni.


Achievement #50 – Limitless Potential: Accept G-Man’s offer of employment.
Story Related. When we appear on the train with G-Man, step through the portal he creates (quickly) to unlock the cannon ending to Black Mesa & unlock the final Achievement.

This directly segues into Half Life 2…

Black Mesa actually blew me away. Having played Half Life 1 for the first time probably five years ago, the fidelity & passion that went into this fan-made remaster is unreal. The soundtrack of all things?! Scripted to perfection & just so on point; truly showcases the power of atmosphere with proper musical cues. I am very disappointed Crowbar Collective will not be remastering Blue Shift & Opposing Force.

My only complaint about Black Mesa is in fact the Hidden Hat & Pizza Box. It definitely detracts from the experience by a lot in my opinion. But that is only because I wanted to do it all in one go… I am sure they meant for players to do multiple runs of the game. 100% took me around 40 hours to complete. This time however, not too much extra time was spent writing the guide with the bulk stemming from the tedium of taxiing the Hidden Hat & Pizza Box throughout the levels... & reloading the same sections over & over again when something inevitably went wrong with them.

If this guide helped you achieve 100%, rate the guide or let me know in the comments. Helps me know if I am doing things right!



100% Complete
Thank you for choosing Cynic, & I will see you in the next guide!

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