Napalm Gun:

Get a perfect head shot on the first three zombies you see off in the distance on the first stage. You'll see a gun on the ground if you did it right.

Red blood:

Beat the game in Original mode. You can now change the blood color at the Options screen.

Golman outfit:

Beat the game in Original mode. The costume will be in the trunk the next time you play Original mode.

Bonus room A:

Get to the final boss and have saved all the civilians to access a secret room with a bunch of good stuff. This room has 3 life ups, 2 diamonds, 2 gold frogs, 2 necklaces, 2 gold coins and a mushroom.

Bonus room B:

Get to the final boss (without saving all the hostages) with over 100,000 points to get an infinite credit power up and a Rogan costume.

Bonus room C:

Get to the final boss (without saving all the hostages) with 70,000 -100,000 points to get a Dynamite Cop costume.

Training and boss modes:

Beat the game in Original mode.

Infinite continues:

Beat the game in training and boss modes. You will get a new 'Free Play' option instead of 'Continue.'

Extra Boss mode options:

Beat Boss mode and get a ranking for all bosses. This will enable "Emperor" and "Fight All Bosses" options.

Show score:

At the Title screen, press Left, Left, Right, Right, Right, Left, Right, Start. You will see a '0' score at the top of the screen to confirm.

Display Score:

At the title screen, when the words "Press Start" appear, press Left, Left, Right, Right, Right, Left, Right, Start on the D-pad. When you begin a game, your score will be displayed at the top of the screen.

Play as Gary:

You must put your controller in the second slot. Now play as Gary.

Goldman Costume:

Beat the game in original mode. The Goldman costume will appear in the trunk of the car in the next original mode game!

Infinity Ammo on Emperor:

Right before you fight the last boss (emperor), shoot outside of the screen 3 or 5 times

Getting a Mac11 in Chapter 3:

Darkness-Before fighting the boss Tower you'll encounter a fat man. The man is doomed, but there is a good chance he will drop an item, it will make your pistol into a mac.11 w/62 ammo.

GameShark Codes: