Valve isn't known for its quick turnaround on sequels, but the Half-Life: Episode 3 developer is certainly reaping the benefits of releasing back-to-back installments in its newest franchise, Left 4 Dead. In October, Valve said that Left 4 Dead 2 had already achieved three times the number of preorders as its well-received predecessor.
Strong preorder demand being a telltale sign of big sales, Valve said today that the Xbox 360 and PC editions of Left 4 Dead 2 have combined to sell more than 2 million units worldwide at retail in two weeks. Valve did not indicate how many units of the PC edition of the game were sold through its digital distribution hub Steam, and declined to specify exact sales figures for Left 4 Dead 2.
According to Valve, Left 4 Dead 2 sales to date have already doubled those of the original. While the studio did not offer current sales figures for the original game, Valve did say in March that Left 4 Dead had sold 2.5 million units at retail.
Left 4 Dead 2 expands upon the frenetic survival horror shooter formula established in the original installment last year. Gamers again find themselves making due with a variety of found weapons, ranging from rifles to chainsaws, and are tasked with surviving the indomitable infected mob. The game features five new campaign maps that can be played in five different modes, as well as extensive co-op support.
For more information, check out GameSpot's previous coverage of Left 4 Dead 2.