This one is designed for competition. Both players have to race each other through the same layout of rooms to reach the exit first which makes it the only castle that cannot be completed alone. I've recorded a longplay of Monty vs me, check it out on YouTube or download it in AVI format (9 MB).

If you're very fast you can fry Frankenstein's monster when it's sliding down the pole in the final key room which should give you an edge over your opponent.