CRASH NITRO KART is basically a racing game. But it's a well-executed, good graphics, and a psycho amount of weapons and dangers kind of racing game! The gist is you chose to either play as one of Crash's team or one of the EVIL team members. Each character has varying levels of speed or turning ability, and this makes it all the more difficult! Add to that the varying levels of tracks, and multiple ways you can play (adventure, single race, time trial, etc!).
People will compare it to Mario Kart, but it's really comparable to any number of racing games from Simpson's Road Rage to Cartoon Network's Speedway. What makes this game tick are the surprises you get as you advance up the game levels. Hidden drivers crop up, new cheats, etc! By the end of it all you can even unlock characters like SPYRO who aren't even in CRASH games usually. This is a lot of fun, and works really well on the GBA. Cute enough for kids, but also challenging enough for adults. I found it actually very challenging to ramp up my driving skills. This was not easy to just pick up and instantly be a pro!