I'm on the latest Opera. Cool game! A few notes, though.
Feature suggestion: An OpenID login would be nice.
Bug: The results page reloads after each fight, very very slowly. As you mentioned above, it's also very confusing since each result displays twice.
https://i.imgur.com/NqBlN.pngFeature suggestion: You should remove the scrollbar seen in the screenshot.
Feature suggestion: You have text as images. You can instead use simple text and custom fonts, which are supported in every major browser (including IE). These text-images aren't even antialiased. So, in your next design update, remove them and use custom fonts.
Bug: It says "ANONYMOUS" in the above screenshot (and on the website), yet on the top it says SeriousWorm (since I updated my nick).
Bug: Every few (5-10?) seconds, I'm guessing on the ajax refresh, the page scrolls to the top.
Bug (maybe): A match (#439) is sitting in Accepted for some time now. It says #439 Waiting for 146.
Weird feature: It seems that I can add BTC to Bitfu, but you said accounts will be wiped. So, if I put 10 BTC to Bitfu, those 10 BTCs will be lost after you wipe the accounts?

Or what?
Feature suggestion: I agree that multiple rounds would be nice. 3 is ideal, maybe an option for 5 rounds, too. An experience system would be cool, too.