Super Mario Galaxy 2/Boo Moon Galaxy

Silver Stars Pop-Up
You start out in a dark room with a small amount of illumination around you. Up in the top right corner of the room a coin marks the doors to the hallway outside. There are Boos in the hallways, so just look at them if they get near you to stop them in their tracks. To the right is a coin and to the left is an intersection. If you take the left fork at the intersection, you'll go down a narrow hallway to the blue warp pad for the time trial with a bunch of Jack O'Goombas you need to ground pound. In the other direction at the first intersection, the hallways will take you around a corner past some more Boos to the Launch Star.
 * First planet


 * Second planet

This planet is full of murky goo that kills you if you fall in. You'll need to run along the pink platforms that go over the swamp to the Launch Star while the planet folds up at the ends. Jump on the first platform in front of you and follow it out toward the Boos circling ahead. Don't bother following the platform through the Boos, just wait until it comes back around and jump the small gap to it (or long jump and spin as soon as you get to the Boos to go straight to the next island). On the other side, grab the checkpoint flag and jump on the platform on the right. This one goes to the right, then straight up to a ? Coin that will release a line of music notes. This one is pretty simple to get, just stay in the middle of the platform and jump across the notes when the platform goes down. When it starts coming back up under the last of the notes, just jump over and spin, landing on top of the platform and three 1-Up Mushrooms will appear for you to collect. When the platform goes back down, hop over to the single line of pink blocks and follow them over to the small ramp where the planet will fold over. This is a short section that goes through a group of Boos to the next ramp. Here the planet folds over one more time and the platform continues on. The platform will make a small jag over to the Comet Medal, then go straight to the Launch Star. If you keep going, you can pick up the hidden star, otherwise, take the Launch Star to the next planet.

This tiny planet is a crescent moon with five Star Chips you need to collect to create the next Launch Star. The planet rocks like a seesaw, so go to one end and run over to the other before it goes down to collect the ones high in the air. When you get them all, jump off the right side of the planet and use the Launch Star.
 * Third planet

You start out in one corner of what looks to be a flat square planet with some Boos on it and a couple Silver Stars. Grab the one in the middle and the one over the button in the bottom right corner and when you ground pound the button you'll see the planet fold up so pillars pop out of the new wall, creating platforms for you. The wall goes back down and comes back up on a timer until you collect the rest of the stars. When the wall goes down when you're on top of a platform, stay where you are facing the Boos so they don't get you, and when it goes back up you'll be on top of it again. There is a 1-Up Mushroom up on the roof, but you'll need to get it quickly, because that area is off the side of the planet when the wall goes down. When you've collected all the Silver Stars, the Power Star will form down on the ground.
 * Fourth planet

Haunting the Howling Tower
You start out in the same room as the first planet, but this time the halls continue on after where the Launch Star was into a maze. You can find two 1-Up Mushrooms inside crystals by exploring, but you'll need to find another hidden door to continue on. Coming from the start, you want to go past the picture of the Boo on the wall and down a hall in the next section with a Bowser statue. After the statue is a dead end around the next corner, but there is a hidden door in the wall you can get through. Go to the end of the new section and jump into the green warp pipe.

Inside the planet you can hit the checkpoint and grab the Boo Mushroom on the platform. Keep going to the right and spin through the grate, then go up past the Octoboo and into the windy hallway. Let the wind sweep you off to the left, but avoid the two hermit crabs in the way. Spin at the next grate, then go up another level past another Octoboo and over to the right and down to another fan, this time blowing upward. It's a tight squeeze between the two hermit crabs and hitting the wall will bounce you off pretty far, so wait until they're separated before going up. Head down the hall to the left going over then under two platforms, then over the last one up into another fan blowing upward. At the top you can spin through the grate, then head right under the hermit crab into the next area. Going down against the wind will take you to a 1-Up Mushroom in a circle of coins. Taking the top path, avoid the two hermit crabs and you'll get another fan blowing upward. This time there are Octoboos in the way, so time it so you can go up between them. At the top you'll be pushed over to the left by a fan and you'll have to go up a long chute with three Octoboos patrolling back and forth. The first one is fairly easy to get past, but the pair at the top are right next to each other, so there is no time to hesitate when going through. When you get past them, you'll see the Power Star in the center of the room being circled by three Octoboos. Carefully make your between them to grab the star and finish the level.

When you finish this level, a Ghost Mushroom will appear in the engine room on Starship Mario.

The Star in the Sinking Swamp (Hidden Star)
The hidden star is on the second planet at the end of all the moving pink platforms going over the swamp. Go all the way to the end where the Launch Star is, but instead of using it, go under it and follow the platform. Right before it sinks into the swamp, another tiny platform will appear. Jump onto it and then onto a small 4×4 platform that will quickly go around in maze-like fashion. Follow the path it creates, being careful not to run into any of the plentiful Boos and at the end you can grab the Power Star.

Green Stars
The first Green Star is on the second planet back where the hidden star was. Go past the Launch Star and take the pink platforms to get to it. You can either long jump back to the left from the platform when it takes its second turn, or follow it all the way around and jump off to the left when you see the star just before the platform goes to the hidden star. The second Green Star is off the left side of the crescent moon planet. Just walk to the left side and jump off then spin over to the star. The last Green Star is on the final planet with the pop out pillars. At the tallest pillar, backflip and spin out to the star to grab it, or long jump from up on the roof where the 1-Up Mushroom is.