Announced at GDC during the Google Play event, Google Play games will now have the ability to play multiplayer with iOS devices. This allows for an even larger community of games and it allows friends to play together regardless of what phone they have (with the exception of windows phones and symbian, sorry). This also forces games to be on the same version across Android and iOS. It might be a slow integration between games but eventually devs should be releasing combine patches.
Two other features announced for Google Play games is the ability to gift in game items among friends in your inner circle on Google+, which just further support the in game monetization of games, and new expanded features to the AdMob platform for ads within games.