Here is the full list of all 19 Last Floor achievements.
Destroy flying alien ship.
You found Secret with a batteries in stairs.
Long look at the Anfisa doll.
You found Secret with a first aid kit in apartment.
Be kidnapped by an alien force.
You found Secret with a first aid kit in bedroom.
Strong vaccum cleaner has ben killed.
Get to the 4th floor. Most of path has been completed.
Alien ship captain was killed.
Received the key to the abandoned room.
You found Secret with a first aid kit in stairs.
Axe for chopping wood found.
Completed all 3 tests: Denial, Anger, Acceptance.
Received the key to the music lover room.
Get to the 9th floor. All still to future.
Mop found.
Received the key to the stairs from Mikhalych.
Make a fall from home.
First acquaintance with a teapot.