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