Here is the full list of all 21 Cubyte achievements.
Experience death for the first time
Sorry no Pizza
Attack an enemy by utilizing its own weapon
Release Cubyte
Defeat Retabyte
Defeat Kibyte
Defeat Professor Byte
Upgrade health to the max
Upgrade speed to the max
Beat the game on normal difficulty
Beat the game on hard difficulty
Obtain the max player level
Beat the game (hard difficulty) without taking damage. Reset game stats if necessary
Talk with all Non-Hidden ICues (in either difficulty)
Purchase all modifications
Consume 30 potions
Kill 2 or more enemies within a single attack