been playing this straight for at least 2 weeks now and i really really love it. the first time i tried it, i didn't like it at all. like the first mission you get - i didn't really understand the mechanics so i got killed like 5 times because the enemies just didn't die
so i came close to uninstalling it. however, read an article about the game and figured out that the whole game world is really molded after the chernobyl area so it grabbed my interest.
bottom line - it takes a minute to get into, but once you master the survival, it's going to be amazing. it's like a combination of halflife2, oblivion, resident evil 4 and something else. i still haven't finished the single player but probably will in a few days and then i'll try the multiplayer.
i can really recommend this to everybody. especially if you're from eastern europe and you're familiar with the whole chernobyl story. the story is amazingly deep and the gameplay mechanics are great. play it for like an hour and i'll guarantee you, you'll be HOOKED!!