Super Mario Galaxy/Gateway Galaxy

Gateway Galaxy is the first level in the game, but it becomes inaccessible after Grand Star Rescue. It is not possible to re-enter Gateway Galaxy until later in the game.

Star 1: Grand Star Rescue
After Bowser's attack on the Mushroom Kingdom, Mario wakes up in this level and sees a rabbit. Follow the rabbit to find two others. The three rabbits challenge you to a game of Hide-and-Seek.

One of the rabbits is inside the crater, a dark hole in the planet with a coin above it. One of the rabbits is hiding in a patch of overgrown grass. The other is inside a pipe. Go to each of these locations to make the rabbit leave the hiding place.

Catch each rabbit by running up to it after it comes out of hiding. The rabbits, when caught, transform into Lumas. If you lose a rabbit, look for a blue line coming out of the surface of the planet.

After you catch all the rabbits, a structure appears on the planet. Climb it and talk to Rosalina. She gives you the ability to do a Spin Attack.

Spin to break the crystals near you. A Launch Star will appear. Use it to go to a hollow planet containing a black hole.

Collect the 5 Star Chips on the hollow planet to create a Launch Star. Follow this to a smaller planet.

Talk to the trapped Luma on this planet. Then defeat the Goombas until one drops a key. Touch the key, and talk to the Luma again. Follow the sling star to another small planet.

Spin next to the giant Goomba on this planet so that it flips over, then touch the Goomba to defeat it and get the key. Go into the pipe that appears on the surface of this planet.

Run over all the flipswitches (yellow squares) to turn them blue. Four of them are below the moving orange platforms. The rest are opposite where you entered, around the Grand Star.

Star 2: Gateway's Purple Coins
Talk to the red star, then collect all 100 purple coins.

Purple coin locations:
 * Floating in bubbles in a ring around the planet (30 coins)
 * On the stairs around the structure where you first meet Rosalina (10 coins)
 * In the lake (12 coins)
 * On rooftops (9 coins)
 * In rings around flower patches (16 coins)
 * Between a flower patch and those green plant things that you can spin into other things (1 coin)
 * On tree stumps (2 coins)
 * On rocks in a path starting from one of the pipes (10 coins)
 * On top of outcroppings in a circle where that path ends (7 coins)
 * In the overgrown grass (3 coins)

Coins
Total coins:
 * Grand Star Rescue: 46
 * Gateway's Purple Coins: 14

Coins that are always accessible:


 * Above the crater (1 coin)
 * On the planet surface (2 coins)
 * Inside a hole that goes through the planet (7 coins)

Coins only accessible from Grand Star Rescue:


 * Inside crystals on the hollow planet (2 coins)
 * Goombas on the hollow planet (2 coins)
 * Inside crystals on the first small planet (4 coins)
 * Goombas on the first small planet (4 coins)
 * Goombas on the second small planet (7 coins)
 * Above the moving green platforms on the second small planet (8 coins)
 * Goombas inside the second small planet (3 coins)
 * Above the moving orange platforms inside the second small planet (6 coins)

Coins only accessible from Gateway's Purple Coins:


 * Goombas on the planet surface that appear after you talk to the red star (4 coins)

1up locations
There is one 1up Mushroom in this level. It's on top of a rock on the surface of the hollow planet in Grand Star Rescue.