A few hours ago, Amazon announced the news that it is working on creating its own service like Apple’s Game Center. It is called GameCircle.
Features of the new service:
system of achievements. Approximately as in Steam;
competition of users among themselves in the sense of points gained in games;
Sync game progress with the cloud. This means that it is possible to continue playing from a saved location, even if the tablet has been lost. It will be enough just to synchronize the device with your account. In my opinion, this feature is the coolest.