Could you add to 'Preview browser' setting option "browse", or something like that. I use Chrome portable and C2 can't find it. Would be good to have an option to browse and set the path to it.
IE9 is really fast! I prefer Chrome, but preview of the latest platform demo still stutters on Chrome and on IE9 is smooth. Hope they'll fix it in Chrome soon, though.
edit> I just noticed, there is a pixel gap under the player's sprite on IE9. On Chrome it's ok.