The first series of planets are disc-like in shape with a grassy top side with flowers and a dirt underside. Mario travels between them using the Floaty Fluff. There are several oddly-shaped planetoids in the Gusty Garden Galaxy which resemble pears. Mario travels between using Sproutle Vines. Most of them are inhabited only by Piranha Plants and Flipbugs. On the final Pear Planet, a Prickly Piranha Plant awaits. After it is defeated, the Launch Star to the next planet will appear.
The next planet is shaped like a curve twisting to the left. On the top of the planet are flowers, a stone pedestal, and more Floaty Fluff, which Mario must use to get to the next planet. Unlike most planets, the underside of this planet is partly covered in grass in addition to the top side. The Puzzle Cube is a cube planet where Mario chases a Star Bunny around, with various small obstacles in the way, like jumping up on the hedge.
There is a set of planets shaped like a question mark which Mario will go to in the second mission. He arrives using Floatly Fluff on the dot and goes the curved part using a Sling Star. He must defeat the Undergrunts to progress between these planets and to the next. The launch star should fire Mario through the Hedge Ring Planet but, he can stop his flight by using one of the Pull Stars. Mario can gather ? Coins which will make multiple Star Bits but, he has to avoid the vines. At one point, there will be another Launch Star to progress.
The next set of planets are the Apples which are increasing size order. There are a few enemies like Wigglers and Flipbugs but the goal is to pound in the stumps to get the giant green worm to burrow through the next apple. The third apple will have a Launch Star to send Mario to the Spiny Planet which has a spiky vine and two stumps. One gives a 1-Up Mushroom while the other makes Star Bits. The Launch Star on this planet will send Mario to Major Burrows.
Major Burrows planet is a round dirt planet with a large tree on top and a series of thorny flowers and crystals at the bottom. Major Burrows is chasing a bunny but Mario grabs his attention and he starts chasing Mario, triggering the boss fight. This planet returns in Super Mario Galaxy 2's Boss Blitz Galaxy where Mario has to face a gauntlet of bosses from both Galaxy games
The third mission sends Mario on the grass sphere planets which is made up of a bunch of grass spheres in a line separated by rings of dirt and thorny flowers. Boulders roll around the planet making it extra tricky for Mario. The Golden Chomp on the planet holds the hidden star in this galaxy. Following the launch star will take Mario to the disk planets where Mario has to collect the Star Chips to progress.These planets consist of a yellow, blue and green set of discs with beige centers and poles. Amps act as the hazard on these planets.
The final planets in this galaxy are the ! and ? Planet which is a gravity switching gauntlet Mario must traverse to get to the power star. Along the way are various enemies including Goombas and Slurples.
- Bunnies in the Wind
- The Dirty Tricks of Major Burrows
- Gusty Garden's Gravity Scramble
- Major Burrows's Daredevil Run
- Purple Coins on the Puzzle Cube
- The Golden Chomp