Batman: Vengeance Cheats (GameCube)

At the main menu screen, press L, R, Y, and X.  If you enter the code correctly, you will
hear a sound.

At the menu screen, press L, L, X, X, Y, X, L, and R.  If you enter the code correctly,
you will hear a sound.

Press L, R, L, R, X(2), Y(2) at the main menu. A sound will confirm correct code entry.

To unlock Joker, enter the password: JOKER4LIFE

Press X, Y, X, Y, L, R(2), L(2) at the main menu. A sound will confirm correct code entry.

Press L(2), R(2), L, R, L, R at the main menu. A sound will confirm correct code entry.