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