Players take the role of stalkers. They explore the Zone and try to survive in that environment. Each of them has its own purpose. The Zone very sensitive reacts to their every act, and the choice of the action can greatly influence not only on their fate, but also on the surrounding reality and to the fate of other stalkers.
In the beginning of the game each player gets a specific task, it's their personal goals, which induced to go into the Zone. Stepping outside the perimeter, they do not have to start to fulfill a task immediately, although it is well rewarded in victory points. They can simply explore the zone and get valuable artifacts. For their task fulfillment and searching artifacts they will receive a certain number of points.
Zone is a dangerous place, full of anomalies and unexplained creatures, a place where the other laws operate, neglect of which means to put themselves under the great risk. The zone is unpredictable. It will evaluate each action and make its verdict to each player.