Enter a race time on the high score screen (make sure the checkpoints are turned on) and type the following on the main menu:
Knacked Reverse tracks
Whoooosh Nitros (hit the horn while racing)
mjcim.rc Small cars
sausage Bonus cars
After entering the codes, make sure you save the game. That way you won't have to go through the whole rigmarole again. Also, if you use the Nitro code, don't try it until you're in at least second gear, otherwise you'll spin out.
