Here is the full list of all 12 The Forgotten Ones achievements.
You did what was necessary.
Got the FG-42.
Beaten the game.
Schienzel is forever dead.
Discover the ritual room
Got the meat cleaver.
You killed the tourists.
You spared the tourists.
Found the book of darkness.
Something is burning...
Use an healthkit at low health.
Got the SVT-40.