S.T.A.L.K.E.R.: Shadow of Chernobyl is a hard game to explain. I'm tempted to label it as simply "
Oblivion with Guns", but that wouldn't quite capture what
S.T.A.L.K.E.R. really is. Initially the game feels like any other FPS. You walk around tight corridors shooting things while all manner of mutated enemies jump out at you. But the deeper you get, the more open the game becomes. Corridors do not feel quite as tight and your surroundings become much more open.
Despite its open feel, S.T.A.L.K.E.R. follows a basic, linear progression. Missions are doled out by the locals. Most are store-based and, unlike Oblivion, there aren't as many "filler" missions to drag things down. Instead, everything is interconnected and feels important, no matter how mundane it may seem.
You are the Marked One; an amnesiac loner stuck in the exclusion zone surrounding Chernobyl, the site of the nuclear disaster in 1986 and, according to the game's story, again in 1989. This second explosion created a mutated wilderness filled with all manner of monsters, faceless soldiers and other oddities. The main plotline takes about 12 or so hours to complete, though there are multiple, optional side-quests that add length. There are also multiple endings which feed off decisions you make during the game.
A bulk of the story is hard to figure out, namely because it tends to show more than it tells. I actually preferred this since it allowed me to experience more of the story rather than have it explained to me; at the same time, anyone looking for a tight narrative may be disappointed.
The main point of the game is to simply survive the harsh, mutated wilderness in front of you. You are not a one man army who can take on everything in your way; you are one person who has to figure out a way to make your way in the world. Where do you go? Who do you trust? These are all questions that pop up throughout the game and each choice comes with consequences. If you join one group, you gain another as an enemy. Choices even go as far as making you decide when to engage members of rival groups since they will hit back hard at you and your faction - removing help you might need later on. There are plenty of "shoot and move on" moments, though most of the game is about careful, smart play.
There are times where even the environment is out to get you; some areas are still contain a massive dose of radiation (which can blind and harm you), while other areas even play with the gravity and physics around you.
Multiplayer options are around for those who want them, though there's nothing particularly outstanding about it. All of the featured modes are standard to the genre, though the maps featured in the game are pretty good and lend themselves to entertaining matches.