Select the "Enter Cheats" option at the main menu,
then press B(2), X, B.
God Mode (for Individual)
Go to enter cheats and enter b, b, x, a.
once in game go to in-game options then enter
cheats after this enter B, B, X, X and all ammo is
refilled. Note you must do this every time you
run out of ammo
Skip Current Mission
Pause the game, go to cheats and press B, B, X, Y and you'll unlock the next level.