Mario Kart: Super Circuit

Need I say more? The game is fun, addictive, great in multiplayer, has tonnes of replay value, as even after you've unlocked the 40+ tracks there's still plenty of high scores to beat as well. Extras like ghost exchange also increase the replay value by quite a bit. Graphically it shows what the GBA can do and it's crisp and clear throughout. In conclusion, BUY THIS GAME. It's the best racing game on GBA by far and, in my opinion, it's the best racing portable game yet!