Here is the full list of all 21 Cubicity achievements.
Obtain all the Achievements in-game
Get to Egypt
Change 6 cubes into magnetic cube
Find the evil scientist portrait
Merge 11 objects
Beat level 2, In world 4 unofficially (w)
Get to 10 hp without dying !
Beat level 11, In world 3, By casting only 1 portal
Let the cubes fly!
Find our logo
Win level without casting magnet
Beat level 3, In world 2, by casting only 1 portal
Obtain a New Weapon
Stuck in level for 5 minutes
Hold 8 cubes at the same time
Get stuck on a level
Win level 4, in world 1, without holding any object
Cast magnet 25 times in one level
Win level without holding object
Let seamus get bored
Launched Cubicity for the first time