EA opening Portal 2

When Portal debuted in 2007, it came as part of The Orange Box, a compilation of several hit games from developer Valve Software. The collection, which also included Half-Life 2 and Team Fortress 2, was distributed by Electronic Arts under its EA Partners program, which offers independent developers a suite of publishing services to choose from.

When Portal 2 was confirmed in March, there was no doubt that the game would be distributed online via Valve's Steam network. However, there was some question about who would handle the boxed copies of the game, which ships in North America on April 20 for the Mac, PC, PlayStation 3, and Xbox 360. Now, though, EA has confirmed that Valve has re-enlisted with EA Partners for distribution of Portal 2 at retail.

Portal 2 follows the events of the first Portal, which saw gamers taking on the role of a human lab rat, Chell, who used a portal gun to create interdimensional openings on ceilings, walls, and floors in an effort to escape the Aperture Science labs. Along the way, players were guided through the diabolical tests by the deceptively sincere, yet altogether sadistic, artificial intelligence known as GLaDOS.

The game will feature a single-player campaign billed as being twice as long as the original's, but the real focus is on the new multiplayer cooperative mode. The co-op mode will tell a parallel story to the single-player adventure and last roughly as long. In it, players will take control of two robots, named simply Blue and Orange, and work together to tackle their own set of portal-related problems.

For more on Portal 2, check out GameSpot's previous coverage.