So here's the story, so far.

  • There are six* Worlds, each with seven galaxies (...whatever). Each galaxy has several stars to collect, some of which are "prankster comet" stars. The prankster comets in SMG2 are more flexible than in the first game; not every galaxy has one, and they can present some pretty weird challenges.
  • * Bowser is at the end of World 6, and you can fight him when you get 70 stars. Beating him unlocks the Special World, a seventh set of galaxies with even more bizarre/awesome challenges. (Beating Bowser also unlocks the ability to switch to Luigi at will.) Between the seven Worlds, there are a total of 120** stars.
  • ** Once you collect all 120 stars, you'll be told to fight Bowser again - after which, 120*** more stars appear. "Green prankster comets" show up, and put green stars in each galaxy; some are hidden just out of sight, while others are right in front of your nose, and require Super Mario precision to get.
  • *** Once you collect all 240 stars, a new galaxy, Grandmaster Galaxy, appears at the end of the Special World. This galaxy is a straightforward but challenging gauntlet, with six phases of obstacles and enemies between you and the final**** star.
  • **** Once you collect the 241st star, and stuff the banktoad full of star bits, a prankster comet appears on Grandmaster Galaxy and challenges you to doing the whole level over again - with one hit point and no checkpoints.
  • Finally, after 242 stars, Rosalina appears and says thanks. Great.

I never did much in Super Luigi Galaxy, because replaying the whole game over as Luigi just sounded silly and unpleasant. But finding SMG2's hidden green stars, while not as exciting as the first 120, is at least enough of a mystery to keep me interested.

EDIT: list update.

Progress: 134 stars

Rating: Awesome