The clearest evidence yet has surfaced suggesting Google is intent on introducing a Game Center-like platform. Mere minutes before I/O, Eufloria HD rolled out an update that explicitly mentions Google Play Games achievements.
Presumably the platform will work in the same vein as other achievement platforms do for iOS and other gaming systems. The changelog says users will be able to sync achievements across your Google+ profile and share them with your circles.
Information is still sparse, but Google is quite obviously going to talk about a new Android gaming initiative. Mobile gaming has become an incredibly popular industry—companies are creating mini consoles solely for mobile gaming—and Google clearly wants to expand on the quality content that’s out there.