Here is the full list of all 27 The Crooked Man achievements.
Beat the game twice
Beat the game without drinking the energy drink
Go back to bed without answering the phone
Try to enter the bed next to D's bed
Get killed by poison gas
Beat the game once
Get Bad Ending 4
Get Bad Ending 3
Finish Scene 4
Finish Scene 3
Don't miss a single shot at the Crooked Man
You shot Fluffy
Read the books in the hospital day-room
Finish Scene 2
Defeat the Crooked Man in Scene 2 without taking any damage
Defeat the Crooked Man in Scene 1 without taking any damage
Escape the gas with over 1 minute to spare
Get Bad Ending 1
Get Bad Ending 2
Try to enter D's bed
Get Game Over 5 times
Read the books in the school
Finish Scene 1
Get Game Over once
Survive first encounter with the Crooked Man
Read the books in the hotel library
Finish the Prologue