TRON:

        On the title screen, hold down 'G' and 'H'.  Now release 'G' and
        press fire.  After you press fire you can release 'H'.  Now during
        play, when ever you need more energy go all the way to the right,
        press down on the joystick, and press 'G' (while still in the
        crouched position).  This will refill your life meter.  This does
        not work on the 1200 due to the keyboard problem.