Launched a series, and almost a subgenre of puzzle-platformers. Wario can't die - instead, enemies afflict him with transformations that are sometimes setbacks but just as often are necessary to solve a puzzle. The most astounding thing about this game is that once you play through its extensive campaign you unlock a “story map” revealing that you've only see half the game, and encouraging you to go back and find secret exits in many of the levels. These are clever and often branch into whole “sub-campaigns” of several levels. It's enormous for a Game Boy game. One of the few games I've 100%ed.