Alongside the promotion, Steam--the installation of which is required to play Call of Duty: Modern Warfare 2 PC regardless of where one buys it due to its use of Steamworks--is temporarily offering 15% off the game's $59.99 asking price, making it $50.99.

Going by Steam, those that haven't purchased the game on PC have "until Sunday" to play it online, with the 15% discount valid until Monday, April 12 at 10 AM PDT. Meanwhile, the game's first add-on hits PC on May 4, bringing five more multiplayer maps. Exactly how much or even if the downloadable content will cost anything on PC has yet to be revealed, though it cost $15 on Xbox 360 and sold 2.5 million copies in the first week.