Cheat Codes Bonus room Successfully complete the game without any hostages being killed. Bonus options in Boss mode Successfully defeat all bosses and obtain a raking for each boss in "Boss" mode to unlock a "Emperor" and "Fight All Bosses" options. Score display At the main menu, press Left(2), Right(3), Left, Right, Start on a standard controller or light gun D-pad. If you entered the code correctly, a "0" score will appear at the top left portion of the screen. Napalm gun Kill the first three zombies in level 1 with perfect head shots. If done correctly, the napalm gun will appear on the gorund. Infinite continues Successfully complete training and boss mode. Then the "Continue" option will change to "Free Play". All items Successfully complete training mode on all five difficulty settings to receive all items in original mode.