Really great game. A good atmosphere paired with good shooting gameplay makes me happy anyday. STALKER has an intriguing story, varied gameplay, and a good range of difficulty. You start wearing nothing but a leather jacket and a pistol, and end wearing an exoskeleton with two rail guns strapped to your back, mowing down an entire military force. I might recommend some overhaul modding to fix up some side quest completion bugs, but otherwise the game is very playable from start to finish vanilla. I really recommend this, it's a classic that you'll really regret missing out on.