Underground CD Volume 1-3 Cheats (PlayStation)

At the "Code Archive" screen of Disc 2, hold Square + Circle and press Triangle(2).

At the main menu of Disc 2, press L1 + L2 + R1 + R2.

At the main menu of Disc 2, press Start.
 

Game Shark Codes

At the main menu of Disc 2, press Triangle, Circle, Triangle, Circle.

At the main menu of Disc 2, press Circle, Triangle, Square, Circle.

At the main menu of Disc 2, press Triangle, Circle, Triangle(2), Square.

At the "Event Center" screen of Disc 1, press Triangle, Circle, Square.

At the "Vault" screen of Disc 1, press Square, Triangle, Circle Square.