In case you haven't heard the news, the wonderful guys at Dezowave have officially released S.T.A.L.K.E.R: Lost Alpha. This is essentially a remake of S.T.A.L.K.E.R: Shadows of Chernobyl, with A LOT of extra content, rebuilt from an early alpha build released by the original developers. Lost Alpha is a standalone game, and, best of all, it is free! Go grab it HERE! A must to all post-apocalyptic gamers and everyone who enjoys sci-fi and first-person sneakers and shooters!
NOTE: The first release has some serious bugs, but Dezoware is hard at work on a patch which will solve all of these, which is due on Mayday (i.e. in 3 days). I recommend waiting until the patch release before playing the game.