One small criticism I guess would be that at first glance it still looks like bitzino requires registration. The "username/password" fields at the top, along with the "register" link makes it look like a traditional site where registration is compulsory, and so may still put off the lazy/casual player. I don't have a clear picture of how it could be better, but thought I'd point it out anyway. Other than that, I think this is a great improvement! 
Flip it around, so auto register is on top and then you get the option to create an account.
As is, it seems like just another button at the bottom of a form & I would personally be "ad blind" to that area, my eyes would skip it because it is below the text entry fields.