Here is the full list of all 19 Comit the Astrodian 2 achievements.
Defeat the True Final Boss
Beat the Game
Beat Planet Starlight
Beat Planet Dark
Beat Planet Red
Beat Planet Blizzcicle
Unlocked Meta Comit
Beat Planet Party
Beat Planet Shock
Collect 50 Red Stars
Beat Planet Mechanos
Beat Planet Aquatica
Collect 1000 Yellow Stars
Collect 25 Red Stars
Beat Planet Paradise
Collect 500 Yellow Stars
Destroy 100 Enemies
Collect 5 Red Stars
Collect 100 Yellow Stars