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