Super Mario Galaxy 2/Puzzle Plank Galaxy

The Puzzling Picture Block
You start out on some large blocks above the planet. Throughout the game you should look out for the star symbol inside a circle you see here, as you can ground pound them. The ones on the ends give you star bits and the one above the platform with the Wigglers below will send the whole block down. On this platform there are four red buttons with the ground pound symbol on them, one in each corner. When you first land, the one in the bottom right will make the Launch Star appear, while the one in the top left will make a series of music notes appear. If you collect all the notes before time runs out you'll be rewarded with three 1-Up mushrooms. You'll want to get rid of the Wigglers first by ground pounding near them to flip them, then jumping on them. use the Launch Star in the center of the platform to go to the next planet.
 * First planet

This is a flat planet with buzzsaws going around the edges. You can actually just backflip and spin up into the Launch Star above, but otherwise you'll need to go to the other side of the planet and ground pound the platforms down so you can use them to get up to the Launch Star. On the other side of the planet you'll find a Hungry Luma who will open up the hidden star for 70 coins and a green warp pipe. Inside the pipe you'll find a room with a ? Coin that makes sets of three coins appear throughout the room. Collect all the coins before time runs out to earn a 1-Up. If you're ground pounding the platforms, make sure you start with the highest one so you can get up there from the lower ones before ground pounding them. Once you do, you can use them on the opposite side of the planet to get up to the Launch Star.
 * Second planet


 * Third planet

Here you'll find a checkpoint flag and a long wooden level filled with buzzsaws. You can see the paths they go in and when they reach the end the cut away part will fall leaving a gap. Most of them just have coins over them, but on in the middle cuts the whole platform, so you'll want to get past it quickly. On the left side you'll also see the Comet Medal before the wall gets cut down letting you progress. Next up, two buzzsaws will cut a chute into the green wall where you can wall jump up to the top. Here you'll need to stay on the move through the green, blue and pink sections, as they're all in the process of being cut away when you get to them. You can grab the 1-Up mushroom on the step at the end of the pink section on your way. When you get to the wooden part, you'll be faced with a Mandibug rushing you that you can either jump over or ground pound to kill. When you make it to the next wooden section you'll be safe until you ground pound the red button on the side, which starts the buzzsaws and creates a small Launch Star. The Launch Star takes you to a little planetoid where you can buy a mushroom from a Shop Luma before hitting the checkpoint and launching to the last planet.

This planet is a simple puzzle where you need to ground pound the three blocks into place to form a picture of a Mandibug. Go along the outer edges until you see the symbols and pound each one three time. Double stacked Mandibugs will drop down and you'll need to defeat them to get the Power Star. The easiest way to beat them is to jump over them when they rush, then jump on top when they slowly back up. Once on top of them they'll stop and you can jump and ground pound. The first time takes out the smaller one on top, after which the bigger one gets mad and turns red, going much faster than before. The same tactic applies though, just jump over it and then on top of it when it backs up to set up the ground pound.
 * Fourth planet

Purple Coin Shadow Vault (Prankster Comet)
This Prankster Comet is a mix of a purple coin and a Cosmic Clone mission. You'll need to collect 100 purple coins while avoiding your clones in one minute. This is a lot like the ? Coin challenge that's down here during the normal star. You have plenty of time as long as you don't have to backtrack, so be careful to pick up each of the four coins in a set of coins so you don't have to go back. You'll also want to take a path that doesn't cross itself, which mean you'll generally want to work from one side to the other. To avoid wasting time jumping up levels a lot, try to get all the groups of coins on one level on one side of the room before moving on to another level.

Bugaboom's Back (Hidden Star)
On the bottom side of the second planet you'll find the Hungry Luma, who wants 70 coins from you to create the new planet. Take the pink Launch Star to a platform with a Cloud Flower and a checkpoint on it. Just the clouds to get to the next platform and again to get to the main planet. Once you get up there you'll meet Bugaboom, a giant green beetle who you previously beat in Super Mario Galaxy. You'll need to ground pound his back three times to defeat him and get the Power Star. The first one is pretty easy as he isn't moving very fast, and is even easier if you have clouds. You can backflip and make a cloud and ground pound right through it when he's under you for the first strike. Afterward he will fly away around the tree dropping star bits. From now on he will be flying, so you'll need to get up higher. He also drops bombs behind him, so you'll need to watch out for those as well. Backflip and make another cloud, then backflip again when he gets close and ground pound in the air to get him a second time. Now he turns red and moves much faster in addition to turning on his side occasionally so you can pound him. Backflip and create clouds twice so you're high above and wait for him to come below you. If he's on his side, don't worry, just jump when your cloud expires and make another one. If he was on his side the first time, you'll be able to ground pound him the next time, or you could get him on his first pass. If you find yourself on the ground, you'll also have to watch out for the water, which will remove your Cloud power. You can also use the jump pads on the sides of the planet to gain height and conserve your clouds.

Green Star 1
The first Green Star is the hardest one to get, because it's high up and it's hard not to destroy the box you need to use to get up to it. On the very first blocks where you start the level, ground pound on the jump pad on one side and hold hard in one direction to avoid hitting the ? square above you. When you get up there, spin and try to get on top of the square or at least grab the edge of it. From the top of the square you can backflip up and get the Green Star.

Green Star 2
The second Green Star is next to the top of the wall that gets cut down by the Comet Medal. After the wall falls, just stand on the half circle left sticking up and backflip and spin up to it.

Green Star 3
The final Green Star is super easy to get. On the planet with all the buzzsaws cutting everything away, just stand in the center of the lower part of the beginning of the pink section, near the 1-Up mushroom. As the pink section gets cut away, you'll start falling and the Green Star will push up through the floor. You can see the rays from the star coming up out of the ground, so even if you're not directly on top of it, it's easy to get to.