When  the  title  screen appears type: qwertyuiop and the message
'Cheat keys (F1-F4) activated' appears. Here's what the keys do:

F1      Restores lost energy to a maximum nine lives
F2      Increases money by one gold piece to a maximum of 999
F3      Increases time by three seconds which gets you a bigger bonus 
        at the end.
F4      Skips to next level.