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Apple’s GameCenter vs. Windows Phone 7 and Xbox Live

As many of you know, I’m currently writing a book to help iPhone developers (as well as non-iPhone developers) adopt the Windows Phone 7 platform called Windows Phone 7 for iPhone Developers. In the course of writing this book, I’ve discovered a lot about the Windows Phone 7 development platform and SDK that I truly love. It really is an awesome platform on which to develop mobile applications and even mobile games.

It’s mobile gaming that is at the heart of this blog post. After version 4.0 of the iOS SDK was released, Apple’s GameCenter was made available. This is an area in which iPhone users can go to see a list of GC-enabled games, find friends, see the status of their friends, and even take part in multi-player games with those friends. Additionally, GameCenter games sport global leaderboards and an unlockable achievement system. I have a few GameCenter games on my phone and, with the release of iOS 4.2, I even have a few GameCenter games on my iPad. The user’s view is that GameCenter’s feature list is incredibly similar to that of Xbox Live as implemented on WP7. However, the similarities disappear altogether when you examine the developer experience.

GameKit is the portion of the iOS SDK that revolves around gaming. Through this API, developers can access a user’s GameCenter profile. They can read to and write from global leaderboards stored somewhere within Apple. For a developer, this is as simple as configuring a leaderboard from within iTunes Connect and then setting some numeric value on the gamer’s profile. This value is compared globally and the leaderboard is computed automatically. For example, if I wanted a leaderboard for “Monster Kill Count”, I would just set the monster kill count for the current player and the leaderboard takes care of itself thanks to Apple’s infrastructure and the GameKit API.

Further, GameKit provides APIs for establishing multi-player gaming sessions with either nearby players (Bluetooth, ad hoc via the Bonjour protocol) or players scattered across the globe. The GameKit API is so easy to use, there are simple method calls for sending data to individual players or broadcasting to all of them. And if you thought that was plenty, add to this the fact that GameKit gives you the ability to, in just a few lines of code, add an overlay channel for in-game voice chat between all connected players. Now if you’re starting to get impressed, think about the fact that NONE of this requires you to stand up a back-end server to support any of this. All of this can be done for ZERO up-front cost, making this an absolute goldrush ripe for the picking for Independent developers as well as prime target for commercial games that support GameCenter features. Oh, and don’t forget the fact that the GameKit API lets you unlock achievements on a player’s profile and those achievements are defined quickly and easily by a developer through the iTunes connect portal.

So how does Xbox Live on Windows Phone 7 fare? Well, this is where the waters get muddy. Xbox Live games have at their disposal leaderboards, lobbies for finding and grouping players, APIs for multiplayer gaming, and APIs for unlockable achievements. So what’s the problem? The first problem is that right in the Marketplace list of conditions for acceptance into the application marketplace is a rule that says your Silverlight application may NEVER make any API calls to any of the core gamer libraries provided for Xbox Live. This immediately rules out casual games written using Silverlight that have multi-player, social aspects.

That’s OK you might be thinking, you’ll just use XNA to build an Xbox game using DirectX9 / Direct3D. You don’t need Silverlight and you do get a flaming truckload of high-end graphics features by going the XNA route. Here’s the rub: You can’t access the Xbox Live APIs unless you’re an approved Xbox Live partner. This means that you must e-mail Microsoft and ask to be admitted into the elite group of Xbox Live partners. Conditions for entry to this club aren’t simple, either. You must already have published an Xbox game to be considered for Xbox Live partnership. I think there are also company size requirements and possibly even a “commercial revenue” requirement. In short, if you’re an indie developer looking to use Xbox Live features, you’re hosed.

With all that said, I wouldn’t be telling the whole story if I didn’t at least explain a bit about why you’re hosed if you want XBL features in your WP7 game as an Indie developer. Xbox Live isn’t just a suite of APIs, it’s an ecosystem. This ecosystem has a currency: gamerscore. This is a point value that every single Xbox Live gamer has on their gamertag. Every Xbox Live game a gamer plays will earn them both points and unlockable achievements. These are global. This means that every XBL gamer can see which achievements you have unlocked and what your total gamer score is – it’s part of your public profile. This is the currency by which relative wealth in the Xbox Live world is measured. Those with higher game score and rarer achievements are this ecosystem’s elite… the upper class.

If an independent developer were to be given unfettered access to the ability to unlock achievements and add points to a gamer’s score, it is entirely likely (if not simply inevitable) that a well-meaning Indie developer would make a game that was too easy, with too many achievements, that awarded too many points. The simple act of a single gamer playing this game and easily racking up its thousands of points and hundreds of achievements would immediately devalue the currency of the entire ecosystem. The hard work, time, effort, and (hopefully) fun players invested in earning their gamer score and unlocking their achievements would mean little in the face of the onslaught of indie developers able to create unbalanced games that respect neither the relative difficulty in unlocking achievements nor their relative worth ecosystem-wide.

GameCenter, despite having the ability to put together players from across the globe, has no global currency. There is no continent-wide Euro with a relative worth standard like the Xbox Live gamerscore. Every game has private leaderboards. The points required to rise up on those leaderboards are not scaled relative to the time or effort required to ascend the ranks of any other game. It might take me 10,000 points to reach the top of a leaderboard in GameCenter Game “A” and only take me 1,000 points in Game “B” but Game “B” might take me 300 hours whereas Game “A” only took me 20 minutes. This type of scale disparity would ruin the value of Xbox Live gamer score but because each GameCenter game is isolated, it has no affect on global GameCenter economy. The same is true for unlockable achievements within GameCenter. GameCenter’s lack of a single, unified currency or score, gives it the ability to allow any developer unfettered access to points, leaderboards, achievements, and multi-player gaming without ruining the ecosystem.

So, in conclusion, it is my belief that until Microsoft creates a mobile, “lite” Xbox Live in which they give developers access to points, leaderboards, achievements, and mobile-isolated multi-player APIs but without access to the global gamer score value, Indie developers will be out of luck.

If anyone from Microsoft is reading this, this is my formal request for such an isolated, “lite” Xbox Live. I realize that Windows Phone 7 is a v1 product, but at least letting your customers (developers, especially Indies) know that you have plans in the works to give us an equivalent of GameCenter and GameKit would go a long way toward platform adoption by Indie developers for casual, multi-player, social games.

BTW, in case you’re curious… the top selling games on the iTunes app store, after you remove the blockbusters by companies like EA, etc, are… drumroll…. casual, multi-player, social games. Here’s to hoping that Microsoft throws us a bone in the near future, or at least something to chew on while we wait for WP7’s sandboxed Xbox Live, if such a thing will ever exist.