Since its launch in late 2002, Xbox Live has taken console gaming to a whole new level, offering gamers a reliable, easy-to-use way to play their favorite games online. Thanks to the friends list and matchmaking features, buddies can battle each other from opposite sides of the globe, or you can play and talk with random gamers you wouldn't ordinarily get to know. It's even managed to extend the life of games in many ways, even those without multiplayer components, thanks in part to periodic downloadable content. While there's no denying that Xbox Live does many things very well, there is one major type of gameplay that has yet to be fully realized: cooperative play.

Now, before I get into the details, it's important to define what I mean by cooperative play. While games like Halo 2, Rainbow Six, and Splinter Cell Pandora Tomorrow all allow you to team up with one or more players to complete a shared objective (such as capturing a flag or killing all of your foes), all of them find you competing against other human players. True cooperative play, on the other hand, enables you and a given number of partners to play through a game's single player campaign. Many games offer up this type of play in a splitscreen mode (or occasionally via the Xbox's system link), but very few allow you to play together online.

Splitscreen? That's so 2001.

Why is it so hard for developers to implement this, you ask? Well, one of the biggest reasons is time (and, by extension, money). Since most developers must adhere to a strict timetable, there usually isn't time to institute all of the bells and whistles that were originally planned. More often than not, a producer will tell me that although they wanted to support co-op play, they decided that it was more important to spend crunch time ensuring that the main game and the head-to-head network code is bug-free. Since it's a completely different type of experience than the standard multiplayer mode, co-op play requires developers to create a second chunk of code, which is no small feat.

With some games, there are also level design issues that must be considered. Most first-person shooters can be played solo or with a friend, and it will essentially give you the same experience either way. Sure, the AI might be tougher and there will probably be more enemies to make the game more challenging, but the levels really don't change at all. However, games like Splinter Cell would be boring with two players, since there aren't very many enemies and the gameplay is fairly linear.