Enter the following codes at the title screen:

-Acid Trip Mode-
Up, Black, B, Left, Y, X , White, L, B , R

-Add weapon option added to the pause
menu-
Up, Down, Left, Right, B, X, Up, Down, Left, Right, B, X

-All Missions and Pictures-
White, Black, L, R, L, White, White, Black, L, R,
R, Black

-God Mode-
Right Thumbstick, Left Thumbstick, Right, Left, L, R, Right Thumbstick, Left Thumbstick, Right, Left, L, R

-Infinite Ammo-
Black, R, Y, White, L, Up, Black, R, Y, White, L, Up