To enter Playstation codes, youll need to first go to the options and select Game Status - hit L1+L2 and youll be prompted to enter a code...
Unlock all arenas/characters (inc. Y the Alien).
Show all the FMV sequences.
Gives your car big wheels (Affects Control/Gravity).
With reduced gravity, cars spend longer in the air.
Allows both players to choose same vehicle in 2P mode.
Interceptor (homing) missiles are much more powerful.
Lets you drive about the levels with no enemies at all.
Ultra-hard (expert) mode.