The game has 14 achievements. Most of the achievements can be unlocked in a single playthrough. There’s at least one achievement that will require a second playthrough to unlock, and only one achievement that requires multiple playthroughs to be unlocked.
If the achievement didn’t unlock for you after visiting the specified rooms or finding the specific objects of interest, replaying the game will eventually unlock them for you.
Off to a Good Start (10 points)
Complete the First Interaction
You'll unlock this achievement automatically as soon as you crawl out of the vent
Turned Around? (20 points)
Solve the Looping Hallway
Click the link for more details.
Up in Smoke (10 points)
Find the Smokers Favorite Spot
Check Special Room: Gymnasium
What have You Learned? (20 points)
Solve the Library Puzzle
Click the link for more details.
Light the Way (50 points)
Find the Hidden Flashlight
Click the link for more details.
You'll be Back... (150 points)
Find the Smokers Lounge
Click the link for more details.
Hurts to Breathe (10 points)
Discover the Tarred Lungs
Click the link for more details.
Don't Let This Be You (10 points)
Find the Ex-Smoker
Click the link for more details.
Open Up (10 points)
Open All Four Drawers in the Morgue
Click the link for more details.
Down the Rabbit Hole (150 points)
Make it to the Sewer Level
Automatically unlocks as soon as you reach the last area.
Not so Pearly Whites (10 points)
Find the Diseased Mouth
Click the link for more details.
One More Out of the Pack (200 points)
Traverse the Maze 20 Times
This requires a total of 20 playthroughs; it doesn’t matter whether you escape the maze or not.
One of Three (150 points)
Traverse the Maze and be Trapped
Deliberately take time navigating the maze until you find the exit leading to an enclosed room.
You're the One (200 points)
Traverse the Maze and Make It Out
Refer to this link for more tips how to find the exit.