2006, almost 20 years after the first incident, a mysterious second disaster occurred, killing or mutating most of the inhabitants. S.T.A.L.K.E.R. begins years later, after people have begun coming to the Zone in search of money, valuable artifacts, and scientific information. In keeping with the post-nuclear decay within the Zone, extreme radiation has caused mutations among animals and plants in the area. As a result of the second disaster, the Zone is also littered with dangerous small areas of altered physics, known as anomalies. Explorers and scavengers operating within the Zone, known as Stalkers, possess an anomaly detector, which emits warning beeps of a varying frequency depending on their proximity to an anomaly. Gameplay S.T.A.L.K.E.R.: Shadow of Chernobyl is primarily a first-person shooter survival horror video game, but it also features many RPG elements. The player does not gain additional abilities or statistics like most RPGs (though the player does level through game play from "novice" to "expert" which has slight effects on the ability to aim accurately), but is instead allowed to attach artifacts which can increase or decrease player attributes. Artifacts found within the Zone have both positive and negative effects except for some rare artifacts which have only positive attributes. There are a large number of items in the game, so the player has customization choices which are constrained primarily by how much exploring they do. The game also attempts to blend the story and character interaction which are commonly associated with RPGs. However, conversation branches are extremely limited and do not significantly influence the course of the game, aside from accepting or declining missions. The Zone itself is a large and varied area, consisting of wilderness, human settlements, and several heavily guarded military bases. However, the game world is not a true contiguous world, but rather 18 different maps separated by loading screens. Transfer from one area to another can only be accomplished at certain specific passageways; wire fences and extreme radiation levels block the player from attempting to cross the map in any other area. Creatures within The Zone are vastly different from their real-world counterparts: dogs, boars, crows, and many more. Additionally, some areas contain mutated humans who have become affected by the so-called Brain Scorcher. Artificial intelligence of wildlife is highly developed and presents many realistic behaviors, such as fights over food and pack mentality, which can be observed in non-scripted events. The