Enable the minnie code. Then, go to "Experiment", get a flamethrower, and start shooting it in any direction. While you are still shooting, press [Enter] to go back to the main menu. Then, go back to "Experiment" (with the minnie still enabled) and shoot your "minnie" gun. The ammo bar (flamethrower ammunition) at the top right of the screen goes down, and goes past the little box it is in. It will continue to go down and off screen as long as you hold the Left Mouse Button.