After learning of his year-long lifespan from Werner syndrome-like symptoms, Snake is tasked by Campbell, now working with the United Nations Security Council, to assassinate Liquid Ocelot. In a Middle-Eastern war zone occupied by one of Liquid's PMCs, Snake meets Drebin, an arms dealer who injects Snake with nanomachines to use the latest weaponry, and Meryl. Snake reaches Liquid, but the latter transmits a signal that incapacitates those nearby with nanomachines. Snake sees Dr. Naomi Hunter, who departs with Liquid.
The overhead third-person view camera of earlier games has been replaced by a streamlined view and over-the-shoulder camera for aiming a weapon, with an optional first-person view like a first-person shooter at the toggle of a button. A further addition to gameplay mechanics is the Psyche Meter. Psyche is decreased by non-lethal attacks and is influenced by battlefield psychology. Stressors (including temperature extremes, foul smells, and being hunted by the enemy) increase Snake's stress gauge, eventually depleting his Psyche. Adverse effects include difficulty in aiming, more frequent back pain and the possibility of Snake passing out upon receiving damage. If Snake kills too many enemies in a short amount of time, he will have a vision of Liquid and vomit, greatly reducing his Psyche. Among the available methods of restoring Psyche are eating, drinking, smoking, and reading an adult magazine.
Source: Wikipedia, "Metal_Gear_Solid_4:_Guns_of_the_Patriots," available under the CC-BY-SA License.
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