Super Mario Galaxy 2/Slipsand Galaxy

Squizzard's Sandy Sinkhole
You start out on a planet of sliding sand formed in a long, curving tube shape. When you jump in the sand you'll slide along with the current, but you need to watch out for spiky plants and fireballs. The first stretch doesn't have anything on it, but it takes you to a platform with fireballs circling it. Run along in the direction of the fireballs and dart through between them to get to the other side. The next stretch of sand takes you through a couple of fireball rings, so if it looks like you're not going to make a gap, pull back on to slow yourself down a bit. The platform on the other side has a couple coins on it, so grab them to fill up your health if you need to, then go across the next short swath of sand to a platform of double fireball rings and a green warp pipe between them on the bottom of the planet. The warp pipe goes down to a room with a ? Coin, and it makes sets of three coins throughout the raised squares. As long as you don't have to go back for any missed coins and you pick a relatively short route, you can earn the 1-Up for collecting all the coins. the last section of sliding sand has spiky plants and four sets of fireball rings, so if you're not good at dodging fireballs, you might want to stay on the top of the planet where you can grab a coin at the end to replenish a health segment. At the end of the planet, use the Launch Star to proceed.
 * First planet


 * Second planet

Here you'll have to go against the current and watch out for enemies and sliding blocks. You can use your long jump to move a bit more quickly through the sand, especially if you get stuck on the wrong side of a moving block. Start moving forward, passing the first block and dealing with the Pokey Heads that pop out of the sand. Time you long jumps at the end to get between the two blocks at the end, or try jumping and spinning to get on top of them and jump from there. Follow the path around the planet and feel free to knock down the Cluckbooms with star bits so you can take them out if they're too aggravating with their bomb dropping. Follow the serpentine sliding sand around past the Comet Medal and over the side of the planet again, picking up the Fire Flower on the way. The Fire Flower will help you take out the Pokey Heads you'll run into and you can optionally use fireballs to destroy the spiky plants so you don't run into them, or light the two torches below the first step to reveal a 1-Up Mushroom. Go up the step and long jump between the first set of blocks, then go to the edge of the platform and jump up on one of the other blocks when they're on the side. From there jump up to the next level, then go around and jump on top of the next block to get to the top of the planet. Grab the checkpoint and use the Launch Star.

In this simple section, just slide down the ramp and avoid the Rhomps that come rolling down past you. As long as you don't over-correct and slide off the ledge or in front of another Rhomp, this should be a pretty relaxing section. The Rhomps come down from behind, but you should have plenty of time to see where you need to be to avoid being crushed. After the last of the Rhomps has passed you, get to the center of the slide, as it narrows down to barely wider than your character. At the end of the slide, grab the checkpoint then hop up to the ledge above where you can use the Shop Luma and the Launch Star to the boss fight.
 * Third planet


 * Squizzard

For this fight you'll be on a slipsand planet with stone platforms around and Fire Flower circling the area in bubbles. The sand slide down to the center of the area where Squizzard awaits, throwing various objects at you and trying to eat you up. If you get hit by anything he throws or if you run into him at the bottom, you'll take damage. However, you can use fireballs to break the balls he throws and to harm him by shooting them into his open mouth.

Squizzard starts by throwing sand balls at you, which you can destroy by jumping on them, shooting star bits at them, or waiting for another sand ball to hit one already on the ground. After he throws three balls at you, he'll open is mouth, making himself vulnerable to be attacked. Grab a Fire Flower and wait for this opening, then shoot some fireballs into his gullet. When you hit him in the open mouth he'll be stunned, so don't stop throwing fireballs at him. Get five into his mouth and you'll do some serious damage and move onto his next attack cycle. For his second attack, he will throw red spiky balls at you and occasionally a yellow one. If you break open a yellow one, you'll get a coin. This time he throws four balls before opening his mouth, and he throws them faster, two at a time. Just like before, grab a Fire Flower and wait for the opening before laying into him with fireballs.

For his final cycle, Squizzard adds two cannons on his sides that shoot the spiky balls for him, after which he throws huge bombs at you. After throwing the two huge bombs, Squizzard will open his mouth so you can attack. It's variable how many spiky balls the cannons shoot at you, so speed up the process, you can take out the cannons with fireballs, forcing him to use his two bomb attack. If you aren't able to beat him quickly enough, any cannons you destroyed will reform and you'll have to take them out again if you don't want to wait for him to throw his bombs. Just like the previous two rounds, it takes five fireballs in the mouth to beat him. When he's dead, grab your Power Star from the center of the area.

Sailing the Sandy Seas
Instead of fireballs and spiky plants this time, the planet is covered with platforms and a few Dry Bones on the unmoving stone parts. On the bottom of the planet you can grab a Life Mushroom in the first sand section by taking one of the circling platforms around. The second section of sliding sand it too long and fast to cross directly, so you'll need to take the green warp pipe on the stone platform with the Dry Bones to head through the center of the planet. Inside the pipe, you'll normally need to go to the left and avoid the two fire wheels and walk all the way around the wall to move gravity, but it's pretty easy to just wall jump up to the right instead and head into the bigger area. Either way, the goal is to get into the orange warp pipe on the wall. The green warp pipe takes you back to where you first entered the underground chamber. If you wall jumped up, so gravity is pulling down, you can just run over the edge and pull back into the pipe to proceed. If you switched gravity in the room on the left first, go around the wall in the big area, then wall jump, spin and pull back into the orange pipe from below. Back on the exterior of the planet, jump across the small patch of slipsand and use the Launch Star on the other side.
 * First planet

Here you'll need to ride the bird-shaped platform just past the checkpoint all the way to the end of this very long stretch of quicksand. Falling in here means death, so stay on the moving platform at all times. The platform itself is semi-destructible, and sections that are hit by cacti or Chomps will be destroyed and will slowly form back up again. As you go through this section, look ahead to where the cacti coming and move to the other side of the platform. In real danger situations, you may need to jump at the last second and spin before landing on another section that is just reforming. Along the way you will also run into Magikoopas, who you can pretty much ignore if you don't mind dodging a couple fireballs and a big Chomp at the end that will chase you all around. You can also pick up a 1-Up Mushroom in the middle, although it's somewhat dangerous as it's right in front of some cacti. For the Silver Chomp at the end that chases you, just try to stay to one side so there is the other side of the platform left when you need to jump to it. At the end, jump onto the stone platform and collect your Power Star.
 * Second planet

Squizzard's Daredevil Run (Prankster Comet)
Repeat the Squizzard boss fight 1 HP. For this star, it's best to just use the fast fireball trick so you don't take any chances, but if you want to fight him normally, all the same rules apply from the Squizzard section of the first star.

Green Stars
You can see the first Green Star on the second planet as you come around from the side with the three Cluckbooms on it. The star is below the platform with the Launch Star, and you can either long jump out from the sand below where you first spot it and spin, or go up to the top and drop off the side. You might want to use the Fire Flower on the spiky plants on the edge of the sand if you're using the first method, although it's entirely feasible to jump from the side of them. Green Stars 2 and 3 are both on the slide with the Rhomps. The second one is on the left edge right in the beginning of the slide before the Rhomps show up, and the third one is on the right edge after the Rhomps have passed you.