...........................I don't know what to say.
When you start the race, the first thing you'll notice is the soundtrack, which is simply awesome. Black Sabbath's Paranoid, Golden Earring's Radar Love, Steppenwolf's Born to Be Wild and the classic Peter Gunn theme are just a part of the best videogame soundtrack ever, included herein.
There's just so many things that were done right with RnRR, it stands as my pinnacle of 16-bit gaming. The control is spot on perfect (esp in the Genesis version), the graphics are colorful and sharp, the level design and enemy AI fantastic, and the replay value is infinite. It improves upon the classic Kart Racing formula by taking random chance almost entirely out of the equation - no longer is it chance whether or not you happen upon a forward firing weapon; you get guns (and mines, etc) loaded up each lap, and must strategically decide when (not if) to blow your opponents off the track. If you've wasted all your weapons before the last section of the last lap just to get there, chances are good you'll wind up on fire in the ditch rather than crossing the finish line with smoking guns.
Play it single or multiplayer, love it, cherish it. Keep on rockin' in the free racetrack.