Here is the full list of all 27 Squarism achievements.
Spend 20 minutes solving single level
Spend 5 wonderful minutes in credits menu
Spend 3 minutes in level selection menu
Solve last level
Solve everything
Finish 60 levels
Destroy your only movable shape
Sacrificed
Finish 50 levels
Opened
Finish 40 levels
Guided
Hivemind
Finish 30 levels
Breached
Use restart 10 times
Spend 5 minutes solving single level
Finish 20 levels
Sticked
Complete level with that huge 4x4 square
Finish 10 levels
Complete level after 5 restarts
Fail level 3 times
Make wrong shape
Complete tutorial levels
Use restart
Complete first level