Welcome to my guide! If you're going for this game trying to game all of the achievements well let me explain why it won't be easy, and it will take all your patience slowly, death by death.

First, there's 28 levels in this game, and you will play through them completely randomly, so the chances of finding new secrets will start to lower later on. Second, the enemies are completely unavoidable, so you're seen and you're dead. There's no way to get around them other than seeing them at a distance and try to hide, and this rarely works.

I may have found a bug that bypasses the death animation and that it opening the Tutorial menu (Default H key) while the death animation is playing. I got it once but haven't tested more times.

There's 3 maze difficulties in this game: Simple, Medium and Hard, with 10 levels assigned to Simple/Medium, and 8 Hard levels. Secrets are scattered around these levels and you might just come across some of them, by complete luck. There's no minimap, there's no map, it's seriously hard complete this game as it comes down to simply luck.

Let the Insanity Decay your Mind
Start a new Game for the first time


Well this one is broken, a great start right? It is however achievable in a depot.
"download_depot 450060 450061 645674732183454629"


I wanna hear you scream
Get killed by the Lagomorph Shadow


The first enemy you will encounter, just let him scream and catch you.


Fear
Get killed by the Colossal Shadow


This one is gonna be your biggest annoyance in this game, believe me. These start appearing in the medium levels.


Decay
Get killed by the Childish Shadow


Bugged. This one triggers when the character is introduced in a cutscene.


Face the Insanity
Get killed by the Monster of the Labyrinth


The Monster are the tentacles around the labirynth, just get close from the ones dropping from the ceiling and they'll catch you.


Laugh Insane
Get killed by the Pale Shadow


The woman that keeps giggling is introduced in the hard levels.


Two faces are better than one
Get killed by the Creeping Shadow


This guy will be on the same levels with the Pale Shadow.


The End?
End a story Mode


Broken! Don't worry there's only one story mode. Achievable in the depot (same one as before):
"download_depot 450060 450061 645674732183454629"

The Insane Decay of Mind
Discover all the secrets hidden in the Labyrinth


This achievement doesn't fit anywhere else and is unlocked upon finding all 40 secrets covered below.

The quickest way to find secrets is to finish the story mode once to unlock the map size select option.
Then just keep restarting maps for ones with undiscovered secrets. Secrets save upon discovery, so you can quit immediately after finding all the secrets on a map.

I will post the beginning of the levels so you can identify them easily and then list the secrets in said level.

Simple 1


Secret: "They could not save this place"
Discover the bricklayer working


Simple 2


Secret: "The sadic teacher"
Discover Miss Janet


Simple 3


Secret: "The stolen book"
Discover Jace the thief


Simple 4


Secret: "Forbidden philosophy"
Discover Abe the speaker


Simple 5


Secret: "Freak Show"
Discover the Circus model

Secret: "Ya Ya, Cthulhu Fthagn"
Discover the strange note


Simple 6


Secret: "An old looking car"
Discover the old looking car model

Secret: "It's so cold here"
Discover why it's cold


Simple 7


Secret: "You can't get rid of the Shadows"
Discover the Colossal Shadow trying to kill you


Simple 8



Secret: "Who's crazy?"
Discover the three version of yourself


Simple 9


Secret: "We have to go far"
Discover why you are in this structure

Simple 10


Secret: "The visits"
Discover uncle Charles visiting you

Secrets are marked on the map. Obstacles aren't marked, but the required tool is always nearby.

Medium 1



Secret: "Bombs are falling down"
Discover what happened to the structure

Secret: "The Landlady"
Discover the lifeless body of the old landlady


Medium 2



Secret: "The Debt"
Discover your mates' quarrel caused by the debt


Medium 3



Secret: "The Rebel"
Discover the rebel of the school

Secret: "A secret code"
Discover the strange code


Medium 4



Secret: "St. Anger Manor"
Discover the St. Anger Manor model

Secret: "The place is falling in pieces"
Discover the broken pipe


Medium 5



Secret: "The Creators of the Labyrinth"
Discover the creators of the Labyrinth


Medium 6



Secret: "Shadows can Fall"
Discover yourself stabbing the Colossal Shadow


Medium 7



Secret: "It's just a prisoner"
Discover the chained Lagomorph Shadow


Medium 8



Secret: "Don't Starve"
Discover yourself eating a rat


Medium 9



Secret: "Scratches"
Discover you scratching yourself


Medium 10



Secret: "Smoking guy"
Discover the misterious smoking guy

Secret: "My Teacher"
Discover the face of your teacher

Due to the complexity of the Hard levels, here's the level designs with the secrets marked:

Minor observations:
- The gas canister is used on the shock symbol (explosion)
- The red barrel is used on the steam symbol (to block the steam pipe)
- The knife is used on the octopus symbol (to cut the sideways tentacles)
- The hammer is used on the fire symbol (to break the water pipe and extinguish the fire)



1. Secret: "A mate of mine was a soldier..."
Discover the soldier mate

2. Secret: "It's a map"
Discover the torn map

3. Secret: "That's not funny, Katy"
Discover one of the thruths




1. Secret: "They've gone far away"
Discover one of the thruths

2. Secret: "Join the Fallens"
Discover something from the future...

3. Secret: "A damp patch"
Discover your mate's memories




1. Secret: "Goodbye uncle Charles"
Discover your uncle dying

2. Secret: "Scratches lie to me"
Discover the scratches on the wall




1. Secret: "What day is it?"
Discover the date of the present

2. Secret: "That's not my school"
Discover where you are




1. Secret: "Looking for a book"
Discover Miss Janet looking for a book

2. Secret: "Is it a dream?"
Discover your alter-ego




1. Secret: "Disturbingly identical"
Discover the Mason twins

2. Secret: "A creepy secret"
Discover something awful

3. Secret: "In goldenyard was my home..."
Discover your home model



No Secrets, not worth playing this level


No Secrets, not worth playing this level