Osmos initially released on the iPad back in 2010 with an iPhone version releasing later, which makes the game practically ancient by App Store standards. The game just became relevant in 2012, as an update with Game Center multiplayer has been released. The rules vary based on the 6 map types available, which are based on modes with in the singleplayer game, but the goal is generally to absorb the other player, or some central object, before they do the same. Levels are designed to be symmetrical, so no one player has an advantage over the other.
This means that games often have an interesting pacing to them: a slow build-up as players try to carefully tread on their way to becoming bigger, then when a player gets the opportune moment to strike, a rapid chase occurs. Of course, sometimes what happens is that one player gets stuck, but might still win if the other player messes up. Or a player chasing after the other might think they have a clear shot at victory by absorption, before a larger mote comes along and drains them enough, sending them careening to their doom. It’s something that makes for a surprisingly great fit with the established gameplay, while adding a whole new dimension to it. The update is live on both the iPhone and iPad versions of the game.