commentary Apple's Game Center should, theoretically, be a service and a hub that ties together gamers across Apple's devices. It should be a social connector, a method of discovering new games based on what others are playing...and a mobile service on the order of Xbox Live.
Right now, it's very little of any of that, largely because the average iOS device owner probably has no idea Game Center is on their device...or what it even is. Regardless, the new version of Mac OS X, Mountain Lion, includes Game Center as one of a handful of more cross-compatible iOS/OS X services. At the moment, its offerings -- connect to leaderboards, see achievements, play cross-platform, and connect to friends -- are limited because, well, there just aren't that many Game Center games for Mac yet.
I logged on to Game Center this afternoon after installing Mountain Lion on my MacBook Air, and found the same set of leaderboards and friend info that I can access on my iPhone or iPad. That's a small accomplishment: it's basically acting like a widget for stored data.
Game Center-compatible titles will have achievements, leaderboard info...and, potentially, a way of playing cross-platform games. As of the time of this post, I could find only seven Game Center games featured the Mac App Store. They're all ports of iOS titles: Real Racing 2 HD, Osmos, Mancala FS5, Spelltower, Anomaly Warzone Earth, Sky Gamblers: Air Supremacy, and Cut the Rope. A few others have started appearing as well, including W.E.L.D.E.R., and more are bound to be updated quickly with Game Center support.
Game Center seems to treat Mac versions of games separately from iOS games, even when they're the same game. Spelltower, once I paid $3.99 for it in Mac form, keeps its own achievements and score rankings from my iOS version.
Cross-platform Mac/iOS multiplayer gaming is, at this moment, a mixed bag. Some games feature iOS/Mac multiplayer (Sky Gamblers, Mancala, W.E.L.D.E.R.), others don't yet.
The thing is, there are actually plenty of cross-platform games out there already: Facebook Connect, for one, enables this for plenty of Zynga games and other titles. Game Center is not a required method for connecting via gaming on the Mac, and that's the key challenge it faces: Facebook, Steam, and plenty of other portals and social communities abound.
The Mac App Store also lacks a complete catalog of Mac games, or any connectivity with Steam for Mac. And, speaking of cross-platform apps, it seems like it's high time for developers to make universal apps that include Mac versions, too. The Mac App Store games mostly cost more than the iOS counterparts (Anomaly Warzone Earth is $4.99 on Mac, $3.99 on iOS; SpellTower, $3.99 on Mac, $1.99 on iOS; Real Racing 2, $12.99 on Mac, $6.99 for iPad), and don't seem to add anything new.
Until Game Center becomes a complete portal for all games on the Mac, and a true method of cross-platform iOS/Mac play, I'm not sure many people will even bother checking it out. When I first tried Game Center on the iPhone two years ago I said, "Until game support reaches critical mass and friend invites become more intuitive, Game Center won't feel like it's second-nature to any iPhone or iPod Touch owners." If cross-platform play really catches on, however, maybe Game Center will finally come of age.