Half-Life 2: Episode 1 won't actually require Half-Life 2 to play, Valve's explained, and although the game will be "four to six hours" long, marketing director Doug Lombardi reckons it's "markedly richer" in terms of content quality. The change from Aftermath to Episode 1 was "simply a name change" he says, when asked about the shift to episodic content - which wasn't a shift at all, he adds, since "the format of episodic releases was decided before Half-Life 2 was made available".

As to pricing and content: "For HL2: Episode 1 we're targeting four to six hours of new single player gaming plus HL2 DM and HL DM: Source for $19.99 - HL2 not required," he confirms. "For Episode 2, we're planning a similar offering at the same price."