To provide a single and complete guide of secrets, I have included all nmo maps from previous secrets guides, credited the original authors and linked their works. I have removed references to deleted guides

For better loading and scrolling, guide parts increased from 4 to 8. Letter b nmo maps are broken into 2 guide parts. All guide parts have a links section that has the previous and/or next part

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Secret Machete

The occupied toilet with feet has a secret


You will need to jump on top of a zombie's head so clear the area of all but the slowest zombie, shove them towards the bathroom stall, jump onto the sink, then onto the zombie's head and then the top of the stall

Jump over to the next stall for a secret machete

Security Room

The room has three codes: 7175, 2105, and 3647

The first code 7175 is in the first office on the way to the access card on the 2f

The second code 2105 is in the office opposite the security room where the access card is found

The last code 3647 is in the security room where the access card is found


The security room has a good stash of supplies

Credit for the secrets on this map goes to Belgrieve, his guide is linked below


When you get to the second street, there is a propane tank to your left in the corner

And there is another in the garage


Bring either across the street to the metal gate at the gun store and it will blow up and allow access

The back door of the store where you get the food/use the radio can be broken open



Destroy the barricade behind the door with a .357, .308, or molotov

To access the rooms behind for a few items

Uzi


At the top of the rope, turn around and jump over the chasm for an Uzi on a ledge

Playable music


In the hotel, door 16 can be opened and the boombox inside can be played

Holy hand grenade


You will find the holy hand grenade in the cathedral. You may need to shoot it down


Pick it up and press e to toss it forward. Can be used 3 times. Be careful as it will instantly kill any players in the large blast, whether friendly fire is on or not

Hidden stash



In this area with stairs, go to the back, head in the water and crouch under the grate for a stash of items behind the pipe

You can use the barrel to help you get out

Welder


You will find the welder in a small room before the garage


Press e on the panel in the room and then stand back for a moment as there will be an electrical surge. After its over, you can open the gate and safely take the welder



Use the welder on either locked door to access the back area of the garage with a weapon box

And to open a weapon locker during the ending event


There is also a sniper roost in an inaccessible area at the end, use a gravity cheat to get there

The key on the jail desk will open the other cell


All of the medical cabinets on this map can be opened for supplies

Diamond key locations

On the computer desk

On a table in the hall before the dining area

On a desk in an office just past the police car

In an open locker in the locker room

On the floor of the room just past where you use the explosive

The diamond key opens the armory



Right where you use the explosive, break the door handle to access the dark office



At the door that partially opens, use an explosive, .357, or .308 to break the cabinet behind it to access the room


Right before welding the lock, weld open the weapon locker on the army truck






3 of the vehicle garages can be welded open for supplies

The box with the chainsaw requires a key


During the event with the moving cart, head into this hallway and move quickly into the vent on the left side. There will be zombies spawning in the hall and gas that will damage you in the hall and vent


Grab the key in the vent and bring it forward with you and you will drop into the earlier vents that connect the first 2 underground areas

Bring the key back to the box for the chainsaw




If you low gravity cheat or noclip and press e on the red handle of the opposite pulley, you can lower the weapon box and health box

Just after using the access card, you can break this door behind the truck for a secret area

Break through the wall here (you'll hear a breaking sound if hitting the right spot), for a stash of items



Break another spot near the first weapon box



Break another spot here for a hidden switch, use the switch to raise the platform

And now you can jump across the platform to the chainsaw

At the starting area, jump onto the shelf to reach a pistol and shot


2008 will open the code door for a weapon bag and supplies (from map page - year of l4d release)

2008 will open the door for a weapon box (from map page - year of l4d release)

Go left in the water and around the truck to find the welder in a small room

Use it to open the weapon box area

Break the barrier in the bottom area for an item stash

Right after you drop down, you'll find a code of 9247 on a shelf


This code opens the keypad door on the first floor of the cabin



In the underground path, break the box near the body before the electricity for a medkit and chainsaw



Hold e on the generator to turn off the electricity



Before you emerge from the underground, you can break the box under the stairs for ammo


The lock to the boathouse can be opened with the red key near the radio or welded

Break the wooden boxes you come across, one of them will have a welder


Use the welder to open the locked shed, it has a chainsaw

The welder can also open a later gate for quicker access to the forklift



If you get the mall/parking lot branching path, a small room before the store has a health box

That can be placed in the store's basement

Drinking from the thermos in the kitchen at start will have a pills effect (Credit to Ice)


Pick up the computer's mouse to turn it on and get the code to the shed

The shed has a health box and chainsaw


Walk up to the ammo pile with any gun and press e to get ammo. There are 60 rounds total so try to get it for the best gun possible




In the area where you use the jack, there is a hammer on the table in the street and extra boards nearby. You can use these to board up the runner entrance near the supply box

This is also where you place the health box from the shed





Instead of using the extinguisher in the supermarket, you can also smother the barbecue fire by bringing all 3 nearby concrete bags



Get the basketball through the hoop 3 times in a row and you'll get a gold trophy


You can drink from another thermos in the kitchen of the last house before the ending for a pills effect (Credit to Ice)


There is another ammo pile at the ending holdout

Go to the back of the apartment buildings, climb up the box and break the window for a secret room with a machete

Oh deer...

One of the hardest parts of this map comes quite early: the deer escape event. Teams will frequently get stuck here as the map gives no idea of what to do

When the event starts, players will be teleported to one of the three deer's backs. In order to complete the event, you will need to stay on the deer's back through the tunnel

Crouch under the ceilings and jump over the logs

Make any mistake or drop off of the deer's back and you will be teleported to a small platform at the end of the event


You can watch the deer as they run from the monster behind them. If no one makes it through the event, then the team will be overrun. New teams and players to this map will need a bit of practice to survive this event




If you make it to the end of the tunnel, the screen will start turning white when you get near the hand pointing down and you will get the message to jump for it. Jump off the deer's back and you will fall through the map and be teleported onto a boat

Special weapons

Healing potion machete



Heals you and nearby humans back to 100hp over an 8 second duration. Does not heal bleeding


The bottle will be empty after use and will need 2 minutes to recharge

Bow and arrow machete


Look straight ahead and press e to use. Fires and arrow that will kill all zombies it touches. The arrow will fly for 4 seconds and the bow will then need 6 seconds more to recharge

Purple knight machete


I can't get this to work. Knight in your face at times. Loud and annoying blade sound effect for every lmb press stays with you after dropping it

Beefy sandwich machete


Summons a beefy ally



Press e and a burly knight will rage and then rush the zombies in front of you

Needs 80 seconds to recharge. When the sandwich has returned, the knight is ready to be summoned again

Use the pistol you find at the soldier's body and a gas can to kill the green zombie

The green zombie will drop a machete and shot



Eat the fish on the second floor down to fully recover health


There is a metal watermelon on the first floor of the building

And there is a movable rag-doll outside

Both can be brought to extraction and will each give a +10 like a normal watermelon

Developer room

Just above the starting area. You will need to noclip there. This is a long map with 3 separate stages (characters). Hold e on the button to start at that stage

Snipe the sniper


Get the sniper before he gets you. If you don't get a sniper rifle in the weapon boxes, there is always a scoped sako and ammo near a body by a truck

Helpful Aliens have supplies

After killing the sniper, find the first helpful alien in a corner at the end of the street

Find the next helpful alien in the same room as the dead sniper and welder

After the building, find another helpful alien going left around the fema trailers

Mini-game for respawn

After you weld and drop down, there will be a short minigame. Kill all the zombies in 60 secs or less and the respawn will unlock

Turret



Use the sniper and ammo at the end of the sewers to kill the turret operator

False wall


After you have killed the turret operator, but before you use the grapple gun, climb up to the sewer across from the turret and break the black (false) wall at the end for another weapon box

More helpful aliens

In the garage, there is another helpful alien with a crank


Use this crank in the area after you weld for a reward of 8 med kits and 8 genes

Fire extinguisher is used on 3 fires


You will have to use the extinguisher to put out the street fire near the City of Dawn sign

The extinguisher can also be used to put out the house fire. But don't try to put out the fire head on or it will damage you


Go to the side of the house to safely put out the fire through the wall

There is a flare gun, flares, and a gas can


You can also use the extinguisher on the other fire in the street

This will make your escape from this map quicker, as you can then climb over the barricade instead of having to go around the block to reach the helicopter

Hold e on the piano for a sound effect. I think this is the first half code hint


Break open the mailbox for extra ammo




Break open the truck for the green key


The green key opens the shed for an extra weapon box


With full health and a running jump, you can make it to the area across the water - just barely


There is a fn fal with 50 extra rounds, 2 medkits, a gene, and an abrasive saw with 35-60 fuel


Go to the green spot and you will be teleported back to the top of the shed

The Brutal Respawn


Press the button to break the nearby wall and start the respawn trap


3 of the platforms will randomly break

In addition, get across quickly as the side walls will be closing in


Get into and out of the elevator fast. The doors close VERY quickly and will not reopen. The elevator will not go back down either

Once you are out of the elevator there is a weapon box with a few items before you drop down into the sewers. Try not to die in the early part of the map


In the sewer, cut the manhole in the stairs

It will lead to a door with a keypad

Second half of the code is above the bed in Ryan's home, break the picture

Code is 6931

The door will lead to an area much like that in the nmo_abandonment map, with a full abrasive saw at the end, but without water



Before dropping down to the final area with the pool, if you can make the difficult jump across to the opposite building you can jump over for a few explosives and the soldier's shotgun and ammo



Hold e on the lantern before the radio to light it

Turret

There is a box of ammo in the armory


Bring it through the sewers and place it on the turret at the map end. Press e to use the turret

When the store breaks open, there is another box of ammo inside

Extra starting firearm


Walk up to this Swat van just outside the starting house and its doors will open for an m16

Supply room


When you reach the sewers, break the barricade on the door facing the entrance for a good stash of supplies

Armory

If you take a right as you leave the last room, or go left from the sewer entrance, you will find the code 2105 in the dark corner

Just down the wall from that code is another, 3647

Go through the nearby passage and you will come to the drainage console which you will use later

North and west of there you will find another code near a barricade, 1854

Break the barricade and you will see a dark doorway under the arch

Head through the passage and you will come to a door with a keypad. 2105, 3647, or 1854

The armory behind has lots of supplies


More supply rooms
The door opposite the armory can be welded

For a small dark room with more supplies

At the end of the sewers, past where the explosive is used, is another door that can be welded

For a small room of supplies

Green key room

At the end of the long hallway, go right into the door marked B

Follow the passage around to find the green key near a body

Bring the key forward with you and use it to unlock the room in the pharmacy

For a small stash of items

Safe



Open the safe just past the pharmacy with the code 52375. This code is painted on the wall in the bathroom where you find the access card. The safe has a tnt

Shutter


Press the button near the fuel to open the shutter for the store and get the fuel out faster

Hidden weapon locker

Just before the bridge, there is a weapon locker hidden in the darkness


It can be welded open for 2 pistols

Weld this extra building for supplies


If you try to use the fire extinguisher to put out the signal fire, you will get a special message

Spare a square



Take the tp roll from the men's bathroom to a locked door in the women's bathroom. Slide the tp roll under the door to unlock the stall

Giraffe spawn locations:

Behind the desk in the first room to the left after the vent

In the room where you find the fuse

In the room where you use the fuse

In the first overlook area

In the later overlook area

Helicopter locations:

Behind the desk before you crawl through the vent

Behind the desk in a dark classroom, the first room on the right after the vent

By the pet carrier in a dark storage room for a bright lab

Behind the desk of the dark classroom with the slideshow


The giraffe and helicopter are both used in the same area for secret rooms


In this same area, look for a small dark office, there is a keypad that when pressed will give the message secret room by lunch room unlocks in 10


This will open a locked door in the next area


Secret sniper stash on top of the vents in the basketball court. Only present on blue key path. Double jump, low grav, or noclip to get up here


The boombox at the top of the stairs will play music


On the green path, you can gravity cheat or noclip up to this secret area

And then gravity cheat or noclip up to another secret area on the big roof

You can safely drop through the vent to return



In the big warehouse near the end, use the moveable box to build stairs, then cross the top of the shelves for items



Break a picture in the captain's quarters after the football field for the secret respawn

Opening the locked door at start




Drop either of the gas can or watermelon onto the nearby body and the door will unlock

There will be a firearm and shot

Three little birds - crow

You can bring the crow at the starting area through the map with you and free it at the end

Extinguish the fire for an sv10

Pick up the fire extinguisher


Put out the fire with it for an sv10

Three little birds - seagull


Press e on the green soda machine downstairs and a seagull will appear. You can bring it through the map with you and free it at the end

Locker

Open the green locker for a shotgun

Parkour secret

In the large room after the shutter, climb up the atm machine to the top of the terminal times

The difficult jump here is one where you use the railing. Crouch jump onto the railing and stay crouched. Think of the railing as a horizontal ladder that you must stay crouched to stay on. You can slide your way over to the top of the lamp


The remainder of the jumps are fairly easy. Jump over to the next lamp and then to the top of the last railing to reach the reward

Three little birds - pigeon

In the large area with the parkour secret, the pigeon is in the center. You can bring it to the end of the map and free it

A few little things


You can jump through the blue void poster for a med item


You can break the glass and jump behind for a shot


You can break the lock for a med item. Do not go in the door opposite or you can get stuck


You can also open the shutter for the resident evil merchant who will have a firearm for you

Three little birds - freedom

You can free all three birds by placing them at the hole in the fence

They fly furiously, but often don't make it far. You don't get anything for this

Run quickly to the machete before the floor breaks

You can drop down safely, the floor is water


Press the button underneath the checkerboard trap

That unlocks this room with a weapon box at the start

At the entrance to the room is a welder

One of the small rooms has a ladder

Weld the hatch and climb up for another weapon box

Behind the big building at the first respawn, there are 2 weapon boxes

Code is 9247, found in the boxes area

Bring the watermelon at the start of the map near the red key

Hang onto the welder from the earlier objective and use it on the shutter in front of the gas station near the end of the map

The room has a weapon box and you can also place the watermelon


The watermelon will activate the nearby coffee machine, press e to dispense a cup and press e again to drink it. The coffee will give you a speed boost

Gene therapy


Climb the boxes outside the gas station and break the resupply box for a shot

Sks in shed


At the shed in the field, stack the boxes and climb them to reach the upper level for an sks

Underground secret area and items


In the underground of the complex, if you remove the 2 explosive barrels that are side by side, you will find a paw print behind


At the end of the underground area, there is gray barrel. Carry this barrel back to the paw print area while keeping it upright - it can get glitchy once its knocked over to its side

When the barrel is in the area with the other paw print, knock it over and punch the paw print on the bottom of it. You need to hit it while the barrel is in the recessed area of the other paw print. If it was successful, you will hear: "hey, uh yeah ... about that cat..."


Go back to the end of the underground area and you will find that a secret area has opened that has a cat poster and 3 special items

Special item box


Its really just special in the sense that you can only get one item out of it and then it will disappear

Magic brick


Has its own trail. Talks. Idk

Explosive barrel generator




Looks like a landmine. Does not hurt zombies. Can be picked up and carried. Moving over it causes an explosive barrel to be spawned nearby. It might explode right on top of you or teammates. Safer in an open area. The light will go back on in 15-20 secs and another barrel can be spawned

There is an often overlooked grenade under the car at start



The purple key that drops with the pliers will lose its glow once the pliers are used. But it can be used to open the next door


For a good stash of .308


Where you move the cabinet, jump up and break this grate

Move the cabinet over, then jump on the desk, on top of the cabinet, then to the vent

Pick up the tnt in the vent


There is a shot here too, but it cannot be picked up

Chainsaw secret


Near the house where you use the lever, walk to the ledge and then drop down into the rock on the left

You will be teleported to a secret room with a chainsaw

Touch the orange tile in the room and you will be teleported back to the top of the chimney of the house. Drop down at the front door to avoid damage



After the gate, go left around the house and break a box for a shot




Break the side door of that house for a stash of supplies and a weapon box


Further in, break the barricades and the door for a bow and arrow stash


The small shed near where you place the smoke device has a resupply box behind it



The house with the alarm has a propane trap you can use on the runners following you. Press e on the left crank to open the gas and then press e on the red switch on the right to light the gas. Can only be used once


The last house before the docks also has a hidden supply of weapons behind it

It also has a weapon box on the roof


There is no way up, but you can use a grenade or tnt to blast the box off the roof and get its supplies

Secret respawn button


Break the barricades and then the door and press the button behind to activate the secret respawn

Many boxes in the early buildings can be broken for supplies




If you get the fix pipe branching path instead of the gather supplies path, you can use the welder on a weapon locker in a dark area



A door inside the bunker will blow off its hinges after the closing has started

The room behind will be full of zombie children, but there is also a shot and another item

Belgrieve's Map Secrets: Official NMO Maps
https://steamproxy.net/sharedfiles/filedetails/?id=2167003980

nmo maps a-boowalk_2018
https://steamproxy.net/sharedfiles/filedetails/?id=3305232181

nmo maps d-f
https://steamproxy.net/sharedfiles/filedetails/?id=3310524255

Follow this guide in-game by using the steam overlay (shift+tab), this and more tips here:
https://steamproxy.net/sharedfiles/filedetails/?id=3294874237

Thank you to all map creators and their contributors!

Thank you to Porkchops4lunch, Kevin, and many others for hosting great modded servers!

Hope this guide brings some love to some old and new maps!

If you liked this guide, give it an upvote (thumbs up) above. Add it to your favorites and it's easier to find in the guides section

Found other secrets for these maps? Let me know in the comments and I'm happy to give credit