Here it is, a WALKTHROUGH!
I looked forever for one of these things...
wasd to move, click on clouds to swing on them
Yellow planet: swing around unti lyou have landed on (and crashed to the planet) all of the moons
Red planet: Find the hole in the surface, and grab on to each gem without touching ground, leave by swinging into the plantes surface
Green planet: swing out of the lower green zone, find the moons sending down ray beams, and swing on them until they die, get all of them
Water planet: swim around until you have eaten all the fish
Earth: return when you have finished all the other planets.