Update: Da_X sent us some addition info: The pictures have been taken from build 1096 from September 2002. This build contains two playable leveles: "escape" and "lest". (there's "zakurat" level too but it's almost the same as the "lest"). There is yet-unfinished AI, so zombies and rats attack you by running towards you. There are also some sounds like firing and some screams. Also in the "sounds folder", there's a russian track that really fits the stalkers atmhosphere. He also mentions that he had 20-40FPS @ 1024x768 on his ancient Duron 750MHz, 384MB RAM and Geforce 3 Ti 500. He grabbed the screenshots at highest settings as possible, there's no AA/AF though.