Type these cheats in the menu while you are not racing. The cheat will be confirmed by a voice saying 'so you want to play dirty'.
VTELO -> Gives you access to all 6 tracks
INVER -> Gives you all six tracks and inverted tracks
CLOCK -> Stops the clock for one race
TAZOR -> Gives you access to the Bullet (rocket) car
ABURN -> Lets you race against Bullet cars
MIRRO -> Mirror mode
MONTY -> Better graphics
JOINT -> More obstacle graphics
Thanks to Revolution readers Frag, DinoBot, and Zachary D.!!