Here is the full list of all 17 Backrooms Break achievements.
Found the gun cabinet key
Died for the first time
Found the elevator
Acquired first gun
Found first weapon attachment
Escorted the ball into the elevator
How do I get out of this place?
Hopefully it's almond water
Get a first kill
Acquired the assault rifle
Acquired the shotgun
Acquired the sniper rifle
Theseus would be proud
..or is it?
We need to go deeper
Kill the invisible monster
Break all the walls in Level 0