All characters:
WATTO_SHOP

Rapid Fire Rate:
FIRERATEUP

Area can be set to no enemies in Battle Mode:
NO_BADDIES

Use the same vehicle in multi-player mode:
MULTI_CARS

Random Races and Opponents:
NO_PEEKING

High Gravity:
BFM_FEELIT

See Winning FMV:
MOVIE_SHOW

See Loser FMV:
SAD_MOVIES

Enter the PREFERENCES option and press L1+R1, after enter a code in the Jedi Mind Trick menu.

Invincibility
"RAISE_THEM"

Low Gravity
"LO_GRAV_ON"

Slow-Motion Mode
"LOW_MO_ON"

Fast Mode
"THROTTLEUP"

All Characters
In order to play as every single character in Star Wars Demolition, enter the Prefernces option and press L1 and R1. Enter WATTO_SHOP while in the Jedi Mind Trick menu.