Off-center in Firefox here, as well, let alone that all that loads is the container.
[Edit] It took a minute, but finally loaded. Still off-center in browser window.
[EDIT] Since my initial post, I've received a new machine from the office and I don't really see so many of the issues I originally cited.
Honestly, I absolutely LOVE the design plan, but running on my box it's buggy as hell. I'd be happy to supply additional information if you can give me specific data you'd be interested in seeing. I'm having trouble ranging from resuming saved games to simple mechanics (too many places where a click is required that shouldn't be, for example). Once this is cleaned up (and maybe I'm a special case and it's not affecting many people), but I agree with other users that this could be a paid title.