Here is the full list of all 10 Return the Backrooms achievements.
Exit ???
Dead or not?
a friend will always help
picked up a strange-looking item
Сomplete the game on easy+ difficulty
Сomplete the game on normal+ difficulty
Сomplete the game on hard+ difficulty
Сomplete the game on very hard+ difficulty
Сomplete the game on very epic+ difficulty
You passed the hardest difficulty level, congratulations, you are invincible!