One of the most unique games I've played.
The main game involves mini-game after mini-game, thrown at you in quick succession. These mini-games have you do the most random things, such as avoid holes in the ground on a dirt bike, eat an apple, count frogs, even stop a booger from dripping out of your nose. All these games last only a couple of seconds. You have no way of knowing which mini-game is coming up next, and unless you've played that particular one before, your only clue on what to do is a one word clue said right at the beginning of the mini-game. With hundreds of different mini-games, there is a lot of variety. This makes for a really fast paced, intense, and fun game.
You also have the option of playing each mini-game on its own, once you have unlocked it. There are a couple of other games you can play, such as the classic Sheriff game, Jump Rope Forever, The Paper Airplane Game, and more. There are also a few two player games, where each player uses one button on the Game Boy. These actually can be quite fun.
The graphics look great. There is a lot of variety, with some games that have very basic drawings, while others are very detailed and look beautiful. The sound is also amazing. It really adds to the quick paced, intense feel of the game.
WarioWare Inc: Mega MicroGame$ is a great game that is loads of fun. The only drawback is it can get old fairly fast, but after giving it a break for awhile, it is still tons of fun to come back to later.