There are four classes of kart in the game, and these correspond to four difficulty levels. The classes are:
- 50cc
- 100cc
- 150cc
- Extra
All cups and tracks are available in each of the four classes. The main difference between the classes is the quality of the computer controlled opponents. They are very mild during 50cc races are rarely attack players. In 150cc and Extra modes however, CPU racers drive very aggressively and frequently use weapons against other racers - they sometimes even appear to cheat! The other main difference between the classes is the speed and size of all the karts. Play the Boswer's Castle to see the difference between the classes.
The major difference between the Extra class and the other other classes is that all the tracks are 'mirrored'. In other words, it is as though you are looking at the track in a mirror. All turns are in the opposite direction to their non-mirrored counterparts and even the billboards around the track are reversed. This mirroring of the tracks effectively doubles the amount of courses in the game to 32. The only note is Extra is the mirror class of 100cc.
150cc has one hazard that can be unpredictable. If you slip on a banana, you can brake until the note above you confirms you have overcome that hazard. But if you steer your kart too wildly, you can also slip into a spin. So try to use the sliding technique instead if you want to avoid another slip up.