Valve confirms plans for Half-Life 2 expansion on Steam

Developer Valve has revealed that it plans to launch an expansion pack for critically acclaimed PC title Half-Life 2 this summer, with the Steam download service being used to deliver the pack to customers.

Tentatively called Half-Life 2: Aftermath, the expansion will allow players to continue from where last year's game left off, and will heavily feature Gordon's sidekick, Alyx - although not, apparently, as a playable character.

Valve's controversial online delivery system, Steam, will be used to distribute the expansion, and it's not yet clear whether the company has any intention of supplying a boxed version for traditional retail as well.

"The reason we're able to do this, and why it's so exciting is because of Steam," Valve designer Robin Walker stated in a PC Gamer interview this month. "If we were doing this without Steam we'd have to put it in a box, we'd have to start figuring out shelf space over a year beforehand. You'd see it six years from now."

It certainly sounds like Steam is set to be the primary distribution method for the pack. The service was also used to distribute Half-Life 2 itself directly, which enraged publisher Vivendi sufficiently to cause an legal battle between the two companies, which is still ongoing.

However, actual figures from the Steam system are shrouded in mystery, as Valve has never revealed how many copies of Half-Life 2 were actually sold over the service - and estimates from around the industry vary wildly from the low thousands into the millions.