Various cheats 

Unlock Everything
     Select story mode, then press Up, Down, Up, Down, L1, L2, R2, R1,
Select  +  X  at the level selection screen. A sound will confirm that
you  entered  the  code correctly. All levels, characters, and bonuses
will be unlocked.

Unlock J. J. Sawyer
     Successfully complete the game with an "S" rank in all levels.

Unlock Naomi
     Successfully complete the Downtown level with a "B" rank.

Unlock Oscar
     Successfully complete the game with an "A" rank in all levels.

Unlock Stunt Attack Mode
     Successfully complete the game in story mode.

Unlock The Insider
     Successfully complete the Storage level with a "B" rank.