Not all browsers implement enough of HTML5 to make it work. It uses HTML5 Canvas and Audio objects, probably other stuff too. It works in recent versions of Firefox, Chrome, and Opera, but not in IE. If your firewall allows *.js files, that shouldn't be the problem.
i'll try when I get home. I have a recent firefox 3.6.6 so that's not the issue.
I'm going to assume it's a firewall issue. I know they block some sites that use the word 'g a m e'. I've even seen specific threads here at the ranch be blocked when they are about such issues. that's one reason why I don't moderate the gaming forum anymore...could never access half the threads while at work.