Increase Weapon Damage
To increase the weapon damage during gameplay, pause the game and then hold down the + and - buttons, and insert the following code: Left, Right, 2, 1, 1, 2.
Unlock everything, the whole damn lot!
To unlock everything in the game, head on over to the game’s main menu. Hold down the + and – buttons, and then insert the following code: Left, Right, 1, 2, 2, 1.
To unlock God Mode, pause the game during the gameplay. Hold down the minus button and input 1, 2, 1, 2.