Well i tried it today and i liked everything except for the shooting itself, its nice that we can use iron sights and turn the crosshairs off but it didnt feel as nice as ArmA, way too 'static' IMO. And i was quite dissapointed that the maps were very thing and long, it made it more or less impossible to get lost which is a shame. Its also a shame that the maps are way too 'filled', every 5 steps you run into an anomaly or a NPC.
Trust me, shooting gets better as you progress on. You will get upgraded rifles with better accurace, more damage, and sniper scopes. Right now I have 4 rifles and one of them is upgraded one with scope. I can do headshots easily. They put crap weapons in first levels on purpose.
And yeah, there are lots of anomalies but they're useless. To get the best artifacts you need to explore for them. Same goes for upgraded weapons and suits.
I think this game is very realistic. It encourages you to approach the enemy carefully and not always engage them. For example, in HL2 you can take out the whole building of enemies without much effort but not in Stalker. In STALKER, I prefer to run away rather engage the soldiers.
Also, ARENA fights are simply awesome. One of the few games where I enjoy fighting against bots.
Graphics are top notch. Environments in DX9 with full shadows own. Luckily, my rig manages to pull off 20-30 stable fps.
btw, I change my opinion. this game is THE GOTY!