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