Here is the full list of all 21 Occult achievements.
5 minutes to stand by the car
caught 25 spiders
kill mediums
kill with train
killed the Spiderlady
defeat the evil
throw a friend out of the cupboard 5 times
big bang
collected 10 jewelry
died from the fall
mirror quest finished
first time stunned by a monster
open 3 locked doors
open lockers and drawers 50 times
25 window jumps
sat in the closet for more than a minute
helped a friend get up
start a game together
complete the game alone
start a four-player game
found the phone and answered the call