If you happen to be a game developer who uses Unity3D to make your games and have been contemplating adding Google's new Google Play Games service to your current and future titles, you'll be happy to know that a developer in the Unity3D community has created a plug-in to make it a little bit easier to integrate Google's service into your games.
The plug-in, called Unity GPG Plugin, just got updated as of a couple of days go with support for the Android OS. That may sound weird at first but that is because the plug-in actually came out for iOS GameCenter support at first while the Android compatibility was being worked on for Google Play Games. This plug-in will let you add a few of the main features from Google Play Games service into your game.
Using this plug-in, you'll be able to add Google Cloud Saving, Achievements, Leaderboard and Sign-in/Silent Sign-in to your games. The developers are not just leaving the plug-in as-is either and are currently working on adding news features to it such as multiplayer matchmaking through Google Play Games. The plug-in is totally free to download and if you want to check it out you can download it from GitHub. There are also instructions over there on how to use it.
Developer Website: Nerdiacs
Download Link: Unity GPG Plugin on GitHub