Unlock All Characters
Go to the preferences menu and press L + R. Then enter WATTO_SHOP at the trick screen. Press X to enable

Go to the preferences menu and press L + R. Then enter the following codes at the trick screen. Press X to enable

SLOW_MO_ON Runs game at half speed
RAISE_THEM Turns player invincible
THROTTLEUP Fast mode
FIRERATEUP Get Fast Firing Weapons
MULTI_CARS Be able to pick same vehicle in multiplayer mode
NO_BADDIES No enemies
BFM_FEELIT High Gravity
LO_GRAV_ON Low Gravity
NO_PEEKING Get random races & opponents
THROTTLEUP Fast mode
MOVIE_SHOW Show end FMV movie
SAD_MOVIES Show losing FMV movie
LOW_MO_ON Slow motion