Mobile as in mobile web, or games compiled in native apps?
games compiled in native apps
I can't think of any that won't require an account. Even gamecenter requires one.
The only other thing you can do is make one yourself with AJAX/PHP.
so there is no 100% user friendly solution for native apps, unless Google service will be supported by C2 or some plugin? // now I forgot to mention about Android //
Develop games in your browser. Powerful, performant & highly capable.
Has anyone actually tried googles games to see if it works with CocoonJS using the gamecenter events?
I haven't, but I plan too. I know the iOS stuff works fine.