At the title screen press Triangle, Triangle, X, X, Square, Circle, Square, Circle. To access the new characters, press L2 or R2 on the character selection screen.

After beating the game, press L1 while selecting a track to unlock a new track.

At the title screen press Triangle, Triangle, X, X, Square, Circle, Square, Circle. You will hear a noise if done correctly. You will be able to play as Leon, Claire, or a Zombie Cop .