Here is the full list of all 35 Ghostly Matter achievements.
Discover the laboratory's password using the Polterscope
Find the Grimoire Power-Up
Find the Laser Sight Power-Up
Find the Ancient Amulet of Fate Power-Up
Find the Sniper Sight Power-Up
Find the Ouija board and summon a ghost familiar
Find the two parts needed to make up the Anti-Demon Kit
Collect all Power-Ups
Kill all enemies using an energy bomb
Stop time using the enchanted hourglass
Complete the prologue
Find the photo of Michael Graves tomb, where Cletus hid the vanished nickel
With the help of the medium, discover the place where the Black Mirror is hidden
Find all 45 documents
Sink the monster in the bathtub using the sacred water
Break all five seals in the Cursed Temple
Find the flamethrower
Find the Laser
Find the Taser
Find the plasma rifle
Find the mega-cannon
Defeat the Gravedigger
Defeat the evil priest
Defeat the sub-demon of Tungl
Defeat the putrid demon of the swamp
Defeat the tentacled monster
Defeat the evil hand and retrieve the tarot deck
Defeat the demon Vargh and recover the Black Mirror
Complete the game
Say yes to a ride to the Pine Creek swamp
Despite the warnings you fell into the Pit of Despair
You made a wish throwing a coin into the well
You've been smashed by a moving column
Use the alembic to distill a fine liquor
You got to the final scene after the credits