Dr. Mario is a classic puzzler that easily stands the test of time; we found it to be just as compelling and habit-forming on the DSi as it has been in any of its other iterations. It's a marvelously intuitive game with simple objectives and even simpler controls. Even rookies ought to be able to pick up the game in just a few minutes. And with multiple levels of difficulty, even younger gamers can try their hand as Nintendo's mustachioed physician. The only letdown is a lack of support for multiplayer. Past Dr. Mario games have offered a great social gaming experience as players work quickly to stymie one another. It's a shame the Express edition doesn't facilitate this kind of play.