Google Play Games, or just Play Games, is a recent service announced by Google at Google I/O 2013. The service allows developers to include several additional features in their games without having to develop those features themselves. These features include leaderboards, achievements, multiplayer, online save, record gameplay, news and updates about games you play, Google+ sign-in, and anti-piracy. All of the Play Games settings can be controlled from the Google sign-in app on Android devices.
The leaderboards allow users to compare their scores to their friends, and to other players all around the world. The leaderboards also allow you to view the highest scores for the game for the day, week, and all time.
The achievements allow developers to encourage players to try different parts of the game, or to try harder to get certain achievements. Once completed.