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