Here is the full list of all 16 Subject 264 achievements.
Launch the game for the first time.
Finish the first puzzle.
Finish the paint puzzle.
Fire is the beginning of the end.
Meeting with an old friend.
What's this place?
Mario? Is that you?
Remember what you have done.
He is always with you.
Why killing her?
What have you done?
What is reality?
Was it the only option?
I am not crazy.
Finish the game without using the free locomotion mode.
Finish the game without using the teleportation mode.