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