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