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