Make Mario a Star
For this first galaxy of the World S, you land on a flat planet that looks like a pixelated 8-bit Mario. This galaxy is composed of blue ?-plates, lava squares and green plates. You must activate all of the blue ones to make the Power Star appear. Just be careful of the green ones that disappear when you walk on them and of the lava squares, of course.
Luigi's Purple Coin Chaos (Prankster Comet)
This time, you land on the other side of Mario Squared Galaxy. It's a pixelated 8-bit Luigi. You have two minutes to collect all purples coins in the level while avoiding the cosmic clones. Just be careful of the blue mud, otherwise you lose a life. You must be fast when you are on the green plates, but you can walk on the yellow ones. Letting some green plates go will make catching the Power Star easier after collecting all purples coins. The cosmic clones are defeated when you get the 100th coin, so don't worry about the end of the mission.
Green Stars
The first Green Star is found below the disappearing platform right behind/above the flipswitch platform with the 1-up. The second Green Star is found on Planet Mario's fist. It is below a platform in the rightmost column.