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