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