One of my favorite shooter/RPG hybrids. But not without a few flaws.
The gameplay is spot-on for the atmosphere and hostile world you're thrown into. You are a Stalker in the Zone of Chernobyl, therefor you must ration, scavenge, and preserve what you have in order to stay alive. The variety of weapons and armor, along with all the healing items you buy, find or take from bodies and Artifacts (Objects that increase/decrease stats) add a very nice RPG element to the game.
The game forces you to be smart about what you're doing, sit there and unload an entire clip at an enemy and 99% of the time you'll just hit air, run out of ammo then get shot down, you have to know when and how to use cover and when to shoot. The way weapons work is very realistic and makes you think about what you're doing. Exploring is also a major part of Stalker, but since the game map is slit into various large sections instead of one giant map, you never really feel like you're "free-roaming".
Along the way you will fight other Stalkers, bandits, mutants of all different varieties and some really weird stuff found in the depths of Labs.
The sound and atmosphere in Stalker is one of the most amazing I've heard/experienced in a game (reminds me of Metro 2033 in some ways).
While exploring The Zone the sounds of gunfire, wild mutant dogs, pigs, etc all sound great but, the atmosphere and sound truly come alive when you enter the Labs. The dark, mutant infested, hell holes provide some of the most memorable moments in the game. I loved the vibe of the Labs, oppressing darkness crushing you with nothing but your gun and flashlight at your side, not knowing if a mutant is around the corner while unseen anomalies throw objects at you when your back is turned. The sounds of eerie screeching, bangs and howls make sure your guard is never down. The encounter of the corpses of Stalkers and Bandits in the labs reminds you that your not the first person who has tried to endure the hell that is The Labs.
The graphics of the game are good, I really like them and think they suit the game. While the engine is showing its age the lighting, shadows and detail gone into recreating Chernobyl are simply amazing. The game can be a bit of a RAM hog at times though, while I've never had this problem because I have 8gig of RAM in my laptop, I have seen this game chew up and spit out my friends computer which has 2gig of RAM.
The story for the most part will most likely bore you at times. The "who am I, where am I, how did I get here). At times the story can also be extremely enthralling though, and getting to/seeing the end is well worth it.
Overall Stalker is a great game and an experience you're not likely to forget after playing. Recommended to anyone who enjoys Shooters with RPG elements with great atmosphere.