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