New car
Beat the basic or Professional Series in Arcade Mode or beat the Champion Mode on Normal or Expert difficulty levels.

Reverse tracks
Beat the Champion Mode on Novice or Expert difficulty levels.

Hidden Bonus Cars
To find the many bonus cars, you must beat the Basic or Pro Series in the Arcade Mode. Each time you beat a series, you will receive a new set of cars. For even more cars, beat the Championship Mode on Normal and Expert.

Reverse Tracks
Beat the Championship Mode in Novice and Expert difficulty levels to get the reverse tracks.

All cars
To get all the cars...at the beginning screen where it has all the options; press R 6 times