Here is the full list of all 22 Witch Hunt achievements.
Make 20 headshots in one playthrough.
Kill 50 enemies in one playthrough.
Kill the beast.
Find all save stones in the game.
Unlock 5 chests in one playthrough.
Attack enemy with lightning using thunder totem.
Attack the beast.
Fire a cannon.
Unlock and visit every location behind locked doors.
Save a dog.
Destroy the sacrificial tree.
Don't get hurt by a whisperer.
Unlock all skills in one playthrough.
Finish the game without dying.
Finish the game.
Kill the witch.
Kill 3 deadblind in one playthrough.
Find the weird looking skull.
Find the book of the dead.
Kill the night flier.
Finish game not using any silver crucifixes or watcher totems.
Finish game in perma mode.