This is the poster-game for innovative ideas, good intentions, and even better vision, that got somewhat lost in the way of development.
The original concept, the crossing-over of game genres, the beautiful graphics, the distant horizon, the RPG feeling (missions, NTCs, journal, etc) of this beautiful FPS game, get mostly ruined by endless glitches of laggings, freezings and overall unfinished development. Luckily, all of the above shortcomings can be fixed by a serious patch.
STALKER introduces a number of very smart gaming ideas, features beautiful environments and manages to create a realistic atmosphere in our room. Nevertheless, this still being an FPS after all, the gameplay is so unbalanced that it feels like swimming in thick syrup: a lot of effort adds up to only little progress.
Nice new weapons that jam all the time. When they don't, it's almost impossible to replenish their ammo. Enemies that seem to absorb bullets like cartoon characters: they go down only after repeated shots!
Your character gets tired and hungry, sure, adds to the realism of the experience - but isn't radiation suppose to cause fatigue as well? None of your enemies seem slowed down one iota...No, I am complaining about the difficulty of the game - it's the unleveled fields that got to me.
Playing STALKER made me nostalgic of the original UNREAL (another game which revolutionized the atmospheric environments at its time). UNREAL however was exceptionally balanced: a head shot with a snipper's rifle would take off both your own head as well as any enemy's head.
Now, I have a pretty decent system (P4 at 3.2MHz with 2GB RAM and a 512MB nVidia 7600GT on an ASUS P4P800), well beyond recommended requirements, yet it was impossible to play STALKER longer than a couple of hours before either the lagging eventually got to me or the whole thing just crashed. The requirements for RAM alone are staggering...
My advice: wait until the next big Patch is available (mind you, patching does NOT support older saved games...)
Recommended only for the next generation of PC systems
(unfortunately, my copy is gathering dust as you are reading this, waiting for my next system).