Peace Walker consists of two primary gameplay modes: "Mission" and "Mother Base". "Mission" are the actual action sequences of the game, where the player must infiltrate an enemy territory or fight a boss, whereas "Mother Base" is an army management mode similar to the briefing screen in
Portable Ops.
Missions Players get to choose which missions to play from the "Mission Selector" screen. There are two main types of Missions: Main Ops are the primary story-based missions in which goals are determined by the narrative and must be played in a strict order in order to proceed. Some Main Ops missions include illustrated cutscenes that involve bits of interactivity in order to proceed. Extra Ops are optional missions that involve much more elaborate goals ranging from simple target practices to obtaining secret documents. When the player completes a mission, their performance is evaluated afterward. A player's score is penalized with a lower rank and reduced heroism for excessive killing and frequently being discovered, whereas players who are stealthy and subdue enemy soldiers non-lethally will be awarded appropriately. Players can replay previously cleared missions for higher scores. The game adopts certain play mechanics from
Metal Gear Solid 4, such as the crouching walk, the over-the-shoulder shooting view, the CQC system, and the ability to search held-up soldiers. The truck from
Portable Ops, where players can bring subdued enemies for recruitment, has been discarded in favor of the
Fulton Recovery System, which players attach to subdued soldiers and prisoners. The Wi-Fi recruitment system from
Portable Ops has been modified so that instead of tapping the Circle button to obtain a strong enough signal from an access point, the player will have to knock out soldiers using CQC to accept them. The cardboard box used to hide from enemy soldiers is now available in two-man versions called
Love Boxes, which have different variants. The Surround Indicator in
Portable Ops can also be used only when it is equipped in the item box and players will also develop and use an early version of the Soliton radar system from the original
Metal Gear Solid. The game features the camouflage index system from
Snake Eater, but the player does not have the ability to change camouflage uniforms during a mission as the point index will be entirely based on movement, position, and the size of the weapon equipped in the weapon box. The player can also use marking devices to call in
artillery strikes or resupply drops. Movement is done on the
analog stick; actions such as co-op actions use the directional-pad; melee actions, which include multiple throws into crowds of enemies, use the R button; and weapons use the L button with the R button. Players will be unable to move or shoot while lying down and while pinned on a wall. The player can set the control system according to that of
Portable Ops,
Guns of the Patriots, or Capcom's
Monster Hunter series. Before starting a mission, the player can choose a character, along with their weapon loadout, which is determined by the wardrobe chosen. Players can choose to control Snake or any MSF soldier assigned to the combat unit, with male and female members both available to choose from. Each soldier has their own combat stats, which measures a soldier's offensive and defensive capabilities. Some of the main missions will only be available to Snake, and likewise for MSF soldiers and certain extra ops. The player's carrying capacity is limited and any excessive items that the player obtains during a mission will be transferred over to Mother Base's inventory. There are four primary types of uniforms that can be worn by the player character. • Jungle Fatigues – The default uniform. A balance of stealth, defense, weapons, and inventory. Alternate versions of this outfit with different colors and camo patterns can be obtained throughout various missions • Naked – A shirtless version of the Jungle Fatigues, players using Naked uniforms move faster at the cost of lower camo index, weaker defense, and fewer items. When worn by an MSF soldier, they will be wearing a brown tank top. • Sneaking Suit – Resembling the sneaking suit worn by Solid Snake in previous
Metal Gear Solid games, it allows players to move without generating foot noise and have higher camouflage compared to other suits while moving, but restricts them to five items and six secondary weapons. The design of the Sneaking Suit worn by MSF soldiers differs slightly from Snake's version. • Battle Dress – A heavily armored suit that allows the player to carry a third primary weapon and absorb heavy firepower, but at the cost of a lower item carrying capacity, slower mobility and a lower camouflage index. A variant outfitted with a metal headband for Snake, or a helmet for MSF Soldiers, is also available, which increases the defenses. Other outfits are also available, such as
t-shirts in various designs,
swimsuits, a
tuxedo and outfits inspired by the wardrobe of supporting characters.
Mother Base Mother Base is an abandoned
OTEC research platform in the Caribbean that serves as the MSF's headquarters. Aside from managing the combat, medical, intelligence, and technology research teams seen in
Portable Ops, the player can assign personnel to the
mess hall crew to feed the troops and keep up their
morale. Rebellious or injured personnel can be brought to the
brig and sickbay, respectively. The player can capture military vehicles that appear in the game as minor boss opponents, such as
armored personnel carriers,
tanks, and
attack helicopters. Up to 350 soldiers can be recruited; excess staff caught in a mission must be discharged and up to 50 vehicles can be captured over the course of the game. Items and weapons are not procured on-site, but rather they are developed by MSF's research and development division based on blueprints obtained from missions. New items and weapons can only be developed when the player has sufficient GMP (Gross Military Product, the player's currency) and certain MSF divisions have reached the required level. Once development of an item has been completed, the R&D staff will automatically mass-produce them for the entire army. Outer Ops is a new game mechanic where players can deploy their combat unit soldiers (with the exception of Snake and other unique characters) and captured vehicles on certain missions against computer opponents. Each assault force codenamed from Alpha to Hotel has eight slots for assigning vehicles or soldiers, who can gain combat bonuses such as additional hit points and Psyche points, and generate income for the team. Depending on the scale of the enemy's firepower, MSF soldiers who are defeated during the battle can either die or be brought to sickbay for treatment. Vehicles that show damage in one mission will still show damage unless they are taken off the front for repairs, while decommissioned vehicles will be stricken from the inventory. During the course of the game, the player will fight advanced AI-controlled vehicles, code-named PUPA, CHRYSALIS, COCOON, and the titular Peace Walker. Each of these vehicles has an AI pod that the player can infiltrate after sufficiently damaging the vehicle in a boss battle, at which point the player must remove AI boards from within to shut down the AI and fully defeat the boss. Depending on the player's strategy in defeating these bosses, vehicle parts and AI boards can be harvested and used to build Metal Gear ZEKE, a bipedal mech designed by Dr. Emmerich for MSF to protect the organization from foreign aggression. ZEKE can be employed on Outer Ops missions as a support vehicle, and its level of development influences the difficulty of the final mission of the storyline.
Multiplayer In addition to the standard single-player mode, most of the missions can also be played cooperatively through an additional game mode called Co-Ops. Infiltration missions during Co-Ops can be played alongside a second player, while up to four players can participate in battles against enemy vehicles and AI weapons. There are several actions that can take place when two players are next to each other. The "snake formation" allows two players to synchronize with each other as one player leads the way, also allowing the players to fire on the move. Other co-operative actions include holding up closing doors, performing
CPR on fallen comrades, sharing items, and acting as a
spotter when a partner's vision is obscured. Versus Ops are multiplayer matches played over special versions of certain maps. The player has a choice of whether to organize individual or team deathmatches, base capture and quetzal capture missions. Only certain items or weapons unlocked in the single-player campaign can be used in the mode. Each match can gather up to six players with restrictions included, such as life and psyche points not regained and limited time for CPR revivals.
Cutscenes The in-game cutscenes come in two different varieties: 3D sequences rendered using the game engine, and 2D
motion comic sequences utilizing an illustration style similar to those featured in
Metal Gear Solid: Digital Graphic Novel and
Metal Gear Solid: Portable Ops. The latter style has gameplay relevance, being host to
quick-time events that have differing effects on the outcome of missions, ranging from contribution to mission rankings, recruitment of personnel, determining mission success, and affecting the outcome of a subsequent mission. The 3D-rendered cutscenes are available with either text-only narration, or with the inclusion of voice acting—the latter requires the decompression and installation of audio data to the PSP storage media, to permit simultaneous audio playback and game rendering without real-time decompression overhead; this feature also permits voiced radio calls during missions. 2D cutscenes are available with full audio support without installation to media. During the Mother Base mode of gameplay, plot details, tutorials, and character interviews can be accessed as well, taking the in-game form of cassette tapes played back on
Sony Walkman players. ==Synopsis==