A masterpiece. The levels are all fun to play, with lots of creative puzzles and boss fights. The score is just perfect. Each galaxy is also unique (mostly, some are just mirrors of earlier galaxies) which keeps the game fresh and fun to play. The creativity and passion the developers had really shows throughout this game. The only downsides are that some power ups kinda suck (spring Mario especially) and purple coins levels can sometimes be a little tedious, however none of that matters, because once you finish the game as Mario you can playing as Luigi.