You will not be able to play the game past "Dark Latex Decision" if you choose "Easy" mode.

Bold lines marked with **n** (where n is a number) are very important to the long-term health of your playthrough. On a related note you can back up your save files by going to the game's folder (usually \Program Files (x86)\Steam\steamapps\common\Changed).

In a number of places you'll be attacked by a monster and have to remove it from you by mashing the spacebar. It's pretty obvious what you need to do in most of these situations, so I haven't mentioned them in this guide, with one exception.

Press the F12 key to instantly jump back to the game's main menu. You can use this to skip game-over animations once you've already seen them.

Look around until a white goo blob appears.
Guide the blob into the drain on the floor.
Then examine the vent it came from.

Look for a note on the wall in the hallway itself talking about a passcode.
You can find the passcode by reading the big panels on the floor. The actual code is 71421.
Hurry to the east end of the hallway after entering the code (hold shift).

Push boxes by using them.
The cat isn't all that smart (it has trouble navigating around large obstacles) and has to slow down every few seconds from exhaustion. Outwit it and escape to the east exit.

The monsters can't see you at all if you're standing still.
Move only when the lights are off. Walk, don't run (mostly). Don't step on the puddles.
You will be caught if a patrolling monster walks directly into you. Watch their patterns.
Eventually a puppy-like creature will run towards you. Once this happens, forget about stealth! (All the monsters will detect you as soon as a puppy reaches you, but fortunately they'll start running much more slowly.) Run east and dodge the creatures as best you can. Don't worry about puddles or strange-looking pillars.

The winged creatures will move one space each time you tap an arrow key. (They're "playful" and wait for you to act.) Don't hold arrow keys down, tap them. Take your time.
Slippery floor lets you move many spaces on only one arrow press. The black round bulbs bounce you a few spaces forward instantly.
Touching the very center space of a large crystal will transform you. You can otherwise get very close to them if you need to.
Go ahead and save when you can.
Eventually you'll reach a room with larger winged beasts that move two steps for every move you make. Don't go down the center of the long slide at the end.

The summoned crystals are "turn based" like the other enemies. Take your time and don't get frustrated, there is some luck involved.
Once you get near the boss, it will stop attacking and you'll be able to proceed.

You'll start in a Big Tree room. You need to head south to the balcony first (unless you cheat and already know the code).
If you mess up the balcony boxes, just leave and reenter. Bait the crow over to the side if necessary.
There's a note in the Moon room giving a clue about the code in the Big Tree room. If the clue is too obscure and you want more help, try examining the note multiple times. (You can't open the locked door in the Moon room yet.)
The code to the locked door in the Big Tree room is 3002 (MOON with the letters rotated clockwise).
East from the Big Tree room is a long vertical room. There's a lot of puddles on the ground, but most will only transform you if you step directly into the center of them. Wend your way through to the north.
Now a fluffy thing is after your rear, literally. Reverse your steps, quickly, and finally hide behind the big tree. Once the fluffy thing leaves, go back through the large room again. (You're going to get very good at passing through this room.)

At this point you can talk to Puro as much or as little as you like without any short or long term risks.
But! Make sure you ask him for "building information" and then "code." He'll give you the code (11100033) for the Moon room's locked door. Now go all the way back and use the code to head east. (I didn't spoiler-tag the code because it's not a puzzle to figure out and you can't enter it early!)

You'll be in a long horizontal room with no real exit but the way you came in, and the fluffy thing will come in behind you. You'll have to run at least a little ways east, run south, and double back west to get back out safely. Watch out for moving shadows.

Go back to Puro and talk to him. (First wake him if necessary.)
**1** Immediately choose to thank him, don't select any of the other two options!
The two doors in the corners will become available now, leading to a western and an eastern room (Puro won't stop you from entering them now). Snoop around carefully. The western room leads into a vent with a clue.
The eastern room is very near to the fox sleeping in the vent.
Step on the white goo in the eastern room a couple of times to wake the fox in the vent.
Run out the door you entered through, then come back in. The lazy fox will be asleep in the room and the entry to the vent will be clear, and the vent too.

Head west at the cross intersection.
**2** Puro will ask you to sit and talk. Go to the beanbag and use it to sit right away, before doing anything else!
Push a box from the southeast up to the north and then around to the northeast so it drops into a hole. Fortunately, once boxes are dropped into holes they stay there permanently. Now make your way south, being careful about how you push the boxes around.
Back in the cross room, now you can push the box out and fill the eastern hole.
Move cautiously into the room until you find a map on the wall. The map will show a secret passage back in the tunnel surrounding Puro's home, south of the first hole you filled with a box. (You can actually cheat and use this tunnel before reading the map at all.)

The maze starts with another hole and another box to fill it with. You should have no problem with this.
Despite its janky appearance, the save point is safe to use. Do so.
Work your way through the maze. It's mostly trial and error, with some game-ending dead ends. Also watch out for partially hidden puddles of goo.
At one point along the correct route you'll find a note with a bunch of arrows on it. Make sure to remember what it says.
Mostly you want to head south and west until you reach a point where you fall over.
Run east and push boxes out of the way until you reach the next room.

You'll come across another passcode box. Try to remember anything hint-like you saw recently.
Use the arrow keys in the order given by the note in the dark maze. The resulting code is 8020 (right right up up left left down down).
Exit the room and the monster that was chasing you before will appear. Don't hesitate just because it's on the other side of the pit, run south and then turn east as soon as you can to loop around the hallway.
You're far from your last save point, so this time I'll warn you ahead of time: you'll be attacked and have to mash keys to escape. Unlike all the others, you need to mash left and right, not spacebar.

The screen will rapidly turn a blue tint as you stay in "bad" spots, soon culminating in a transformation. Most places are "bad." Safe spots will take the blue tint away.
Most safe spots are in front of fans. A corridor very close to the start appears to be a "stealth" safe spot, though.
Make your way through, running in and out of safe places to keep the blue tint down.
Don't miss the save point embedded in a fan box about halfway through.
When you encounter the puppy, try to lead it as far back as possible, move forward to the edge of the left hand fan box, then run when the puppy reforms.
**3** Talk to Puro as soon as you see him and immediately choose to thank him, don't choose one of the other two options.

Enter the water at a corner to bait the shark into coming close, then move over to run past it.
Go west, bait both sharks, turn on the power, and go back out.
Go south and run across the pool right away. After turning on the power, make sure you find the save point before getting back in the water.
Start heading back north. Outrun and juke the boss and dodge its summons. After its third roar you'll be able to escape to the north. Don't assume you're safe once you get on land, get through the door!
**4** Talk to Puro, who should be asleep. Choose to wake him, then choose to wait by him.
Keep going east. Bait all four sharks into a corner before making the run across, be patient.
Try to make all four of the tentacles charge into their master in the center. Good luck. You can retreat west and save your game after the battle.
Different monsters than sharks, same bait and run tactic.

If you're stumped, try going back out to the west. The code is 1234.

The game will end here if you haven't completed all 4 starred **** tasks above (or if you're playing on Easy difficulty).

Talk to Puro, he'll tell you about the secret doors nearby. Enter the one on the right.
You'll end up in a huge foreboding white room. Three waves of white latex beasts will appear as you head north.
The white pillars are like the big crystals from back near the start of the game, you can get very close to them if you don't directly walk into their centers. I rushed my way forward past the third wave, personally. Stay strong.
Use the computer and exit back to the south.
**1** Puro will be here. Talk to him and then let him catch up to you before exiting the big room. Make sure he talks to you at the southern end before you walk out.
Now enter the secret door to the left.
**2** Talk to Puro again, after he charges past the white latex beasts in this room and draws them out.
Run back into the door when the lion pushes Puro aside. Now you'll have both the lion and the white beasts to deal with (you should have known you wouldn't have gotten through this room that easily). You'll probably have to do some experimentation to figure out a way through this. Stay strong.
Hide in the steel cabinet. Exit the cabinet when the lion is checking the left-hand door. Yikes!
**3** Return to Puro, talk to him, and thank him.
Enter the secret door over to the west.

Looks like you're in trouble now. Examine the button on the floor, look for another one.
Without Puro around you're going to need to find another ally.
Look for the floor robot and wave to it through the glass. Now its movements will mimic your arrow key presses. It will move even if you're blocked (and won't move if blocked, even if you move). Guide it so you and it step on your respective buttons simultaneously.
The next room is more of the same, but, of course, harder. Watch out for the headless dogs, they have a small detection range but they're definitely not dead.
The next room has transformative gas. You know what to do.
Once you've escaped, return to where you were before.

If you haven't completed the last 3 starred **** tasks above, the game will end here.
Otherwise things are very straightforward until you reach the next area.

Look in the southeast room for a note with a hint. If you want more help in-game you can examine the note repeatedly for more tips.
The code's digits are written somewhere on the floor of each room, one digit per room.
You need to brute-force guess one of the digits.
The code is 0815.

A circle of white latex beasts will appear around you. Turn and "use" Puro and he will throw you forward! Run east.
Do something similar in the next room. You may need to move up and down a bit to make sure there aren't straggler beasts getting stuck on things distant from you. Try to wait until the last second.

After everything you've done so far, this should be pretty easy. Slide into small crystals and don't slide into big crystals, and take your time. Try a different route if you end up trapped with no safe way out.
No more sliding puzzle? Many little crystals in the floor? Almost there. You don't need to use shift here and it's probably a bad idea too, but you do need to keep moving constantly. Watch out for little blocking crystals hidden out of view behind the big crystals.

Sometimes, when you're forced to choose between two terrible things, it's better to vote "no."
There's a key on your keyboard you probably haven't used all game, even though it was listed in the controls near the start.
Instead of choosing one of the two options, press Escape.