Full list of all 27 Superliminal achievements. It takes around 8-10 hours to unlock all of the achievements in the base game on Windows.
The base game contains 21 achievements, and there is 1 DLC pack containing 6 achievements.
Finish the game with developer commentary enabled
Finish all challenges in Challenge Mode
Contribute an item to the Workshop
Import a 3D model into the game
Play someone else's dream
Upload a dream to the workshop