Abbrevation for Metal Gear Solid 4, a PS3 game by Hideo Kojima.
In the latest addition of the Metal Gear Franchise you take on the role of
Old Snake, who has aged rapidly due to the mutating
FOXDIE virus in his body. In this, probably, last version of Metal Gear Solid it is up to you to stop your evil brother Liquid Snake from taking over the world.
MGS4 is a PS3-exclusive and will not release on the other gaming platforms.