GSC Game World has released a version of S.T.A.L.K.E.R.: Shadow Of Chernobyl, dated October 18th, 2004. The old build contains everything that had been built to that date, which includes levels cut from the retail release, and also game features that THQ cut to help make the game more palatable to the mass market. Word is: "The build uses a completely different physics engine than the one used in the final retail version.
This build is fully playable and contains all of the original levels as well as those that were cut such as Dead City, Swamp and Generators."
