Super Mario Galaxy 2/Rolling Masterpiece Galaxy

Silver Chomp Grudge Match
In this galaxy you move around by jumping on the Star Ball in the beginning and running on top of it. Hold the remote pointing straight up in the air and tilt it in the direction you want to go. The faster you tilt, the faster you go. You can also jump with. On the starting platform, jump on the Star Ball and take it over to the end of the platform and jump up where the star bits are circled around a hole. Guide the Star Ball into the hole and it will shoot you over to the first planet.

This small, multi-colored planet has a ton of paintbrushes sticking up out of the ground creating walls. You'll see another hole like the one you took to get here when you land, but it's protected by a glass cage and you'll need to find the key to open it. The key is in the green section inside a semicircle of green paintbrushes behind where you land. You can also grab a 1-Up Mushroom in the green section. When you have the key, return to the hole where you landed in the red section and take it to the next planet.
 * First planet

You'll land in circular depression with colored panels all around it and a checkpoint flag on one side. Jump out towards the checkpoint and follow the blue and green blocks as they form a path in front of you. They'll take you around to an elevator with three Goombas on it and a 1-Up Mushroom if you keep going down the path beyond it. Jump up onto the elevator and it will take you to the top. At the top you'll need to turn all the blue ? panels to yellow ! panels by rolling over them. Just like when you're running on two feet, going over a panel twice will turn it back to blue so don't backtrack. When you've got them all, they'll turn green and a large ruler will appear over to another launch hole.
 * Second planet


 * Third planet

This planet is a curved wooden platform full of buzzsaws cutting parts away and Goombas. Jump out of the depression you land in, hit the checkpoint, and start making your way down the planet. Down the center is the Comet Medal and off to the left side is a ? Coin that will make a line of musical notes appear. Follow the notes and you'll earn three 1-Up Mushrooms for picking them all up. In the middle of the planet, jump up the switchback ramps and rush through the next section where multiple buzzsaws are cutting away by jumping over the raised platforms. At the end you'll take a large yardstick out to another platform with a Silver Chomp in the middle and circular wooden platforms in each corner. Take the offensive early and push the Silver Chomp off the platform. Keep pushing in the direction of the edge before it has time to recover and come after you. When you've defeated it, a ruler will appear and you can roll to the next platform where the Star Ball will break and the Power Star will be released. Climb to the top of the flag pole and jump up to the star to claim it.

Masterpiece Speed Run (Prankster Comet)
For this star, you have to repeat most of Silver Chomp Grudge Match with a few exceptions in a two minute time limit. You can go straight ahead on the first planet to find the key to the glass cage in the blue section instead of where it was before in the green section. The second planet is the same—follow the blue and green path to the elevator and turn the blue panels yellow. Instead of going to the wooden planet with the buzzsaws and Goombas, you'll go to a green planet with a bunch of holes and Bob-ombs everywhere. Like the third planet from the other star though, there will be a ? Coin on the left that will create a trail of music notes you can collect for three 1-Up Mushrooms. At the end you'll take a launch hole to the Silver Chomp fight which is the same, and the countdown will stop as soon as the Power Star is freed from the Star Ball.

Green Stars
After launching from the planet with the paintbrushes where you needed to find a key to open the launch hole, you'll find the first Green Star on the left side of the elevator as you're going up. You'll need to balance right on the edge to get it, so kill off the Goombas as soon as you get on so they don't bump you around. If you miss it, don't worry because the elevator goes back down again. The second Green Star is above the far left corner of the platform where you fight the Silver Chomp. Just roll right off here, don't jump, because your character needs to go through the star, not the Star Ball.