You can't beat STALKER. I've tried pretty much every game out there but, I've found none that put me where this game does. I start playing and get lost in a world that can be both beautiful and terrifying. I remember my first visit to the Yantar lab in SHOC. It was in the early hours of the morning, I was using headphones while sneaking around the lab. The atmosphere had me on the edge of my seat. Ten seconds later something totally unexpected happened and put my heart in my mouth. I paused the game, shaking like a little child and from that moment on for me it has been the stick by which all games are measured. And sadly they just don't measure up. STALKER is a thousand games in one. Set in a constantly changing, evolving world. The only time any two playthroughs are the same is when you hit that ENTER THE ZONE button at the start of the game.
This mod contains loads of maps including many I haven't seen before, I've done a machine translation for it and a small fix patch. To download the mod you need the main mod link and a patch link, both are on the mods AP forum site.
Then you need the translation, also use the small fix that's included with it, It won't matter which you add first.
UPDATE: This link goes to a site with a few small fix patches you need,