Will have to check when I get home but the controllers are cheap and cheerful, work well when they work but not every game recognises them. The keyboard controls are fine anyway! :-) Didn't think of downloading the Xbox driver though, thanks for that will give it a try.
Points reverting to zero when you Continue is fine, this is what all the old Taito coin-op conversions did IIRC. Younger players won't be bothered about the score anyway, they will just be happy to carry on playing.
Another idea is (maybe) the Gauntlet method - i.e. as long as one player is still alive, the other can bounce back in when they lose their last life (with points set to zero). This does mean you can basically go on forever as long as you don't die at the same time - might not work well for your game but just an idea to consider.