Super Mario Galaxy 2/Haunty Halls Galaxy

A Glimmer of Bulb Berry
You start out on an open platform with a walkway perpetually moving toward you. Across this red carpet are two groups of Boos and some ? squares. There are only three Boos in the first set, and they slowly circle around, but the second set has twice as many, leaving only one gap to get through. At the other end you'll find the Launch Star and a warp pad to the time trial down a few stairs off to the side. The time trial is full of Jack O'Goombas, which you will need to jump and ground pound to defeat quickly enough to get the three 1-Up Mushroms. The Launch Star back on the planet will take you to the next area.
 * First planet


 * Second planet

Here you'll want to run down the moving walkway as it drifts from left to right. Follow the walkway without stopping and while dodging the Boos and you can make it across to the next stationary platform before it drags you into the wall on the side. The first green walkway moves fairly slowly and you should have no trouble keeping up with it even if you make a mistake. You can even long jump over some of the shorter gaps at the end to speed it up. You'll reach a checkpoint flag, then the next walkway is red and moves from left to right. You can pick up a 1-Up Mushroom along the way and will need to dodge through a gap in the Boos toward the end. The next walkway is green and move much more quickly from right to left. You'll need to make a couple 90° turns to the right along the way, and don't make the mistake of going back toward the camera when you have the chance. Next up is another red platform going left to right. After you run up the sets of stairs, you'll have to wait for a moment and jump the gap in the walkway to the left. At the end is a green warp pipe surrounded by circling Boos and the Comet Medal.

You will end up inside a place with bookshelves and large sections of the floor, walls and ceiling missing. Hit the checkpoint, then grab Yoshi and eat the yellow Bulb Berry right next to him. This will create a circle of light around Yoshi that will reveal the structure wherever it touches. It slowly decreases in size, so you'll need to move quickly to the next safe platform or find another Bulb Berry. Hitting a Boo while relying on the Bulb Berry will knock you off Yoshi and extinguish the light, spelling instant death.
 * Third planet

Start out by heading down the invisible walkway and taking a right at the end where the next Bulb Berry is to find the key that unlocks the door. Grab the Bulb Berry, head through the door, and either go down the steps in front of you for a 1-Up Mushroom guarded by a Boo, or take a left and head up the stairs to continue on. Up the stairs, go right and jump the small gaps and grab the Bulb Berry, then head down screen and take the stairs to the right. These lead down to a landing with a Smeech on it and a doorway you can go through. On the other side of the doorway, go down the hall to the right, jumping the gap in the middle, and start climbing up on top of the bookshelves. At the top use the pull flower to jump into the Power Star.

Sneaking Down the Creepy Corridor
Everything starts out the same as the previous star, except when you get to where the warp pad to the time trial is and where the Launch Star used to be, the platform just keeps going, although it's no longer moving. When you get past the sign in the middle of the walkway, a group of Boos and a Mega Boo start following you. It's not a problem, just keep going ahead like you normally would and take the Launch Star at the end. You'll have to keep on the narrow path and don't linger on the green disappearing squares.
 * First planet

Here the camera is fixed and you start out by going to the right. When you get past the checkpoint flag, a Boo will appear behind you, so either don't stop or turn around and face it if you need to plan your next move. Start out by waiting for the floating platform to come over to you at the end of the walkway, turning to face forward when you hear the sound of another Boo who is appearing ahead of you. Jump off the platform on the other side and come downscreen toward the camera. Along the walkway here you'll need to avoid the Mattermouth as well, so turning around to stop the Boos isn't going to be an option. Stay to the right to avoid it, and wait for the platform at the end of the walkway, making sure to face the closest Boo at all times. The next walkway also goes downscreen toward the camera and another platform at the end. This once takes you to a mini Launch Star.
 * Second planet

With the camera behind you once again, you can see what's coming up, which is a long walkway with a bunch of Mattermouths chewing it up. The platform is moving toward you, slowing you down, so you may need to long jump as well to stay ahead of the enemies. Stick to the right side of the walkway until the first Boo shows up and then pick your jumps according to where there's walkway to land on. At the end of the straightaway is a stone platform with another Boo in front of it and more platform curving out to the left. Head around this walkway with the Boos chasing you while avoiding Mattermouths. At the end is another solid platform where more Boos and a Mega Boo appear behind you and you'll have to run toward the camera again. Instead of a walkway, you'll need to jump across lines of moving stone squares alternating going in different directions perpendicular to your path. When you get to the large stationary red platform past them, run across the green disappearing tile and jump the gap to the ones beyond where you'll find the star.
 * Third planet

Spooky Cosmic Clone Chase (Prankster Comet)
This Prankster Comet requires you to complete the last planet from Sneaking Down the Creepy Corridor while being chased by Cosmic Clones. If you were able to get that star, you'll be able to do this one, since it's the thing, except you can't stop. Use the same route as before and take advantage of the speed boost you get from long jumping to get past the Mattermouths. Besides the clones, the only difference from this section in the previous star is the Boos don't chase you in the last part and you'll need to spin the crystal at the end to destroy the clones and free the Power Star.

Green Stars
The first Green Star is beneath the first platform, right under the blue warp pad. Hop off the side and spin over to the star. You can see the second Green Star in the intro scene when you fly into the galaxy and when you use the first Launch Star to go to the second planet with the green and red walkways that move across the corridor from wall to wall. When you first land there, you can see the star's shadow along the first left to right section of the walkway. You can head down the walkway and triple jump up to the star, or just run down the walkway when it first appears on the left and crouch for a blackflip and spin when you move under the shadow.
 * Green Star 1 or 2

The green star is in the very last section of the galaxy on the moving red and green squares right before the Power Star. You won't have a lot of time with the moving squares and the Boos behind you to do a backflip and spin, so it might be easier to try for a triple jump up to the star.
 * Green Star 3