Here is the full list of all 25 HITLER: BDSM BUNKER achievements.
Find a grenade launcher
Get all the videos in the gallery
Go through the third location
Find all the notes in the third location
Find all the weapon enhancements in the third location
Go through the second location
Find all the notes in the second location
Find all the weapon enhancements in the second location
Find a rifle
Find MP 18
Find all the notes in the first location
Find all the weapon enhancements in the first location
Kill 10 enemies
Kill 15 enemies
Kill 20 enemies
Kill 25 enemies
Kill 30 enemies
Kill an enemy with a headshot 10 times
Kill an enemy with a headshot 15 times
Kill an enemy with a headshot 20 times
Go through the first location
Find MP 40
Kill Zombie Old Crone
Kill Zombie Brute
Kill Zombie Butcher