Here is the full list of all 27 Squarism achievements.
Spend 5 wonderful minutes in credits menu
Solve last level
Solve everything
Spend 20 minutes solving single level
Spend 3 minutes in level selection menu
Destroy your only movable shape
Finish 60 levels
Finish 40 levels
Finish 50 levels
Opened
Sacrificed
Guided
Hivemind
Finish 30 levels
Spend 5 minutes solving single level
Breached
Use restart 10 times
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