Successfully complete the game on the ultimate difficulty setting. Then at the title screen, press L, R, L, R, Start. If you entered the code correctly, you will hear a sound.

Successfully complete the game on the ultimate difficulty setting. Then at the title screen, press L, R, L, R, Z. If you entered the code correctly, you will hear a sound.

Successfully complete the game on the ultimate difficulty setting. Then at the title screen, press L, R, L, R, A. If you entered the code correctly, you will hear a sound, and the word "Extra" will appear at the lower right corner of the title.

Learn more fighting abilities

Note: A lot of life chargers are required for this trick. You have to fight the mutants to learn different types of fighting moves. Fight one over and over again by going back into the room. Sometimes the best thing to do is to allow a mutant hurt you first. A "bing" sound will indicated that you have learned a new fighting ability. Do not forget to save the moves.

Avoiding fights

You do not have to fight all enemies. You can run past them or get across pits with enemies by jumping in the pit, running to the other side, and jumping out.

Full power and overall advantage in fights

When you walk into some rooms they will contain people that you will have to fight. To get the overall advantage over them, allow them chase you around the room until you get behind them. When you get close enough, "Advantage" will appear at the top of the screen. Not only will you have the advantage, you will start with full power and will take more of the creature's life away since you attacked from behind.