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