Here is the full list of all 12 RocketGO achievements.
Finish all stages in Planet Hollow
Finish all stages in the game
Have all updates
Found all Alien Gears
Finish all stages in Planet Inferno
Finish all stages in Planet Storm
Finish all stages in Planet Acid
Finish all stages in Planet Wave
Have one update
Finish all stages in Planet Ruby
Found one Alien Gear
Finish one stage