MGS: Peace Walker is an action-adventure stealth video game and is the third action-based Metal Gear title made specifically for the PSP, following Metal Gear Solid: Portable Ops and its stand-alone expansion Portable Ops Plus, and the first in the series released for a portable platform to be directed by series' creator Hideo Kojima. This is the first title in the series to alter the traditional tagline "Tactical Espionage Action" to "Tactical Espionage Operations", referring to the base building and mission mechanics of the game.
Set in 1974 in Costa Rica, the game follows the exploits of returning protagonist Big Boss (previously known as Naked Snake in Snake Eater and Portable Ops, now known simply as Snake) as he runs the mercenary unit Militaires Sans Frontières (Soldiers Without Borders).
Peace Walker consists of two primary playing modes: "Mission" and "Mother Base". "Mission" are the actual action sequences of the game, where the player must infiltrate an enemy...