Setsuzoku no Puzzle, or Puzzle of Connections, is worth a playthrough just for its synthy score; besides, downloading the homebrew game and listening to the music tracks takes little to no effort. Actually clearing a level or even learning how to attack the puzzle, however, will require a considerable amount of work.
Modeled after Match It, a 1989 arcade game, you'll have to knock out 140 tiles against a timer. Each multicolored square has a symbol -- moons, stars, and other Lucky Charms marshmallows -- that you can link with an identical piece to remove them both. Though your connecting line can stretch all the way across the playing field, the catch is that the link must turn no more than two corners to be valid.
You'll suffer several frustrating losses before you get to the point where you've trained your eyes enough to spot similar tiles, but the satisfaction that comes after everything "clicks" and you complete a level is ample reward. If you get stuck, you'll be able to hit X to have the computer eliminate a match for you several times. Head past the post break for more screenshots of the homebrew puzzler.