It translates to Grey/Green/Not sure because there is no 'Arcade' genre.

As far as I know, providing it fits the multiplexity theme, which it appears to from what you've said, providing of course its all Pascal, which I assume it is because otherwise you wouldn't be asking, then you could enter it.

And yes, registrations are still open.

WILL or Savage will need to confirm it, but I don't see why you can't enter it providing you've complied with all the competition rules. And I think the same will go for any late comers to the competition.