As the original power-up-loaded go-kart racer, Mario Kart can hardly be called a derivative, cash-grabbing franchise. Well, that used to be the case, anyway - Double Dash!! pretty much offers just one new thing for us to scream about, and that's the ability to control two drivers on one extra-long kart.
For the first time, you can choose, say, Mario and Luigi simultaneously, and swap between them mid-race. Mario drives while his bro acts as a gunner, tossing turtle shells and slipping banana peels on the track. The trick is finding a good balance of characters to put in these extra-long, pimped-out karts. Too bad the player combinations rarely, if ever, affect your ability to race.
While the karts may handle similarly - some are slow with a high top speed, others accelerate quickly but aren't speedsters, and so on, but the differences are actually minor - each character's special weapon is what makes or breaks the race. Yoshi and the suspiciously gendered Birdo both toss homing eggs that explode into useful items, Wario and Waluigi have a massive bomb to leave behind and Bowser can shoot a spiky shell that plows through everything. These are just a few examples of what you're gonna have to put up with on the Mario Kart circuit.
And that's the true advantage of Double Dash!! - its unrelenting action. Some of these new shortcut-laden courses are designed so tightly that there's just no way to keep your lead. Soon enough, you're barreling down the stairs of a cruise ship or power sliding through Donkey Kong's dense jungle brush - all areas that you'll see in some fashion in other kart games, but rarely crafted so clearly as in Mario Kart.