TRAINED ASSASSIN:

        Let the demo start then hold down '2', '4', 'Y', 'L CURSOR', and '7'
        (the 7 on the keypad).  This will give you infinite lives.  

        Hold down 'A', 'T', '.', '4', and 'ENTER' (not return).  Now use
        'F1-F5' to skip levels.