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