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