Re-Volt

All cars:
Enter CARTOON as a name.

All tracks:
Enter TRACTION as a name.

All weapons:
Enter YOY as a name. Press L + R to change weapons.

Tiny mode:
Enter MAGGOT as a name.

Change cars:
Enter CHANCER as a name.

Enable UFO:
Enter YUEFO as a name.
(Information from Cheat Machine)