Invincibility:
Enter ''EMERPUS'' as a code at that "Enter Cheat" screen.

Invisibility:
Enter ''SLLEWGH'' as a code at that "Enter Cheat" screen.

All weapons:
Enter ''TEXAS'' as a code at that "Enter Cheat" screen. Note: You will only have the weapons that are available in the current level, not all the weapons in the game.

Infinite ammunition:
Enter ''MADMAN'' as a code at that "Enter Cheat" screen.

Big head mode:
Enter ''HEID'' as a code at that "Enter Cheat" screen.

Zoo mode:
Enter ''ZOO'' as a code at that "Enter Cheat" screen. In this mode, you will be able to kill any animal in the game with the war club as a weapon.

Demo mode and target mini-game:
Enter ''HUNTER'' as a code at that "Enter Cheat" screen. Besides starting demo mode, you will also be able to play the Target mini-game at the main title screen. Use the D-pad to move the pointer and Fire to shoot.