Here is the full list of all 32 44 Minutes in Nightmare achievements.
Watched the entire opening
Dived into the nightmare for the first time
Dived into the nightmare 10 times
Dived into the nightmare 30 times
Dived into the nightmare 60 times
Killed a zombie
Killed a knight
Killed a maid
Killed a puppet
Killed a nightmare demon
Burned a voodoo
Opened a secret room
Woke up from a nightmare
Opened the door of a shrine
Opened the wall of a church
Opened the bookshelf of a study
Fell into the depths of a nightmare
Heard the ending music all the way through
Escaped with less than five minutes remaining
Escaped within the first 10 minutes
Clear short mode
Clear hard mode
Escape alone
Killed 4 enemies in 1 game
Opened the hidden room
Cleared without recovering a single mental pollution
Turned on all lights installed in 1 game
Cloth over all dolls in 1 game
Map not used, rest points not used, all exits opened, burned the voodoo, opened the secret room, and opened the hidden room in 1 game