Metal Gear Solid V: Ground Zeroes acts as the prologue to Metal Gear Solid V: The Phantom Pain. Series creator Hideo Kojima decided to release Ground Zeroes as a separate product in order to ease players into the open world structure and other gameplay changes. The story of Ground Zeroes shows how the 40-year old protagonist Snake (Big Boss) (not to be confused with his clone/son, Solid Snake) falls into a 9-year coma, leading up to where The Phantom Pain begins. The game released with both retail and digital versions for Xbox 360, Xbox One, Playstation 4 and PlayStation 3 on March 18th, 2014.
After the events of Peace Walker, Kaz heard from "friends" inside the secretive Cipher organization that Paz had resurfaced in a clandestine prison camp run by American forces off the coast of Cuba called Camp Omega, along with their young ally Chico.
Cipher reportedly thinks that Paz is a double-agent, while Kaz and Snake (Big Boss) are both afraid that Paz might sell out the truth about Militares Sans Frontieres (MSF; Soldiers Without Borders). To complicate matters further, the UN (with US forces) plans to inspect Mother Base for nuclear weapons to determine whether or not MSF poses a real threat to the world.
Snake decides to infiltrate the prison camp to rescue both Paz and Chico, and hopefully convince Paz to join MSF for real. Unfortunately, the inspection team will be arriving the night he leaves for the prison camp, and Kaz warns Snake that he will be on his own without MSF backup for this mission.
Snake arrives quietly at the base and manages to rescue both Chico and Paz. Aboard the helicopter, it is discovered that a live bomb was surgically implanted into Paz's abdomen, which is promptly removed by a medic accompanying the extraction.
Snake arrives back at Mother Base to find it under heavy attack--the inspection team was a ruse to get an assault force access to the base. Snake attempts to fight back, but he is forced to extract with Kaz and fly away as the base explodes and crumbles into the ocean. Paz stands up in fright and begins to reveal that a second bomb was implanted in her before throwing herself out of the helicopter and exploding. Their chopper goes down, leading to the beginning of Metal Gear Solid V: The Phantom Pain.
Unlike previous Metal Gear Solid titles, Ground Zeroes puts Snake into a more open world environment built to allow players to approach objectives stealthily from multiple directions as well as multiple methods, such as by vehicle. Similar to Metal Gear Solid 4 however, players control Snake via third person camera and aiming, with first person viewing mechanics as well.
During a mission, at any time Snake can drop a flare to signal a helicopter that can be used to transport to different locations or even "other countries". The helicopter plays a tune chosen by the player when approaching (like Flight of the Valkyries), though if this tune is too loud, or if the helicopter is too close to enemies, it can be shot down and Snake's cover can be blown. Once on the helicopter, players travel in real time and there are no loading screens to get to the destination.
The helicopter can also take players to their base at any time during the game. Players are able to walk around the base, and have the ability to design it.
Snake also carries with him some sort of holographic projection device that is used to display the map and his relative location in real time without a pause menu.
The game also features day/night cycles which are supposed to enhance re-playability by mixing up enemy patrol patterns, for example.
PlayStation Exclusive Content
The PS4 and PS3 versions of the game will feature the exclusive mission "Deja Vu". This mission will take players back to Metal Gear Solid brought to life with the latest Fox Engine. Players can unlock and control the MGS1 version of the original Metal Gear protagonist, Solid Snake and Cyborg Ninja Gray Fox.
Xbox Exclusive Content
The Xbox One and 360 versions of the game will feature the exclusive mission "Jamais Vu". This mission will have players controlling Raiden as he appeared in Metal Gear Rising: Revengeance, fighting Body Snatchers that have taken control of a U.S. Naval Facility in Cuba.
At the Metal Gear 25th Anniversary event, Kojima Productions showed a 20 minute demonstration of the FOX engine and the game to attendees. Photography or video was not allowed, although excited reactions from attendees surfaced via Twitter.
Konami has released a promotional image from the demonstration. The character appeared to be Big Boss, indicated by the "Militaires san Frontieres" patch on his shoulder and his sneaking suit (from Metal Gear Solid: Peace Walker). The image shows a deliberately backwards phrase that when flipped reads as: "From 'FOX,' two phantoms were born." The meaning of the phrase has yet to be fully detailed.
A few days later at PAX Prime 2012, Kojima showed the same trailer and gameplay at his "Past, Present, and the Future of METAL GEAR" panel, and shortly later released it online. The trailer was as much of a reveal of Ground Zeroes as it was for FOX Engine. Setting for the footage was a military base during a heavily rainy night, showing rain and wind effects. Also detailed was plot for the game, and Snake's objective at the facility.
Shortly after PAX Prime 2012, Kojima tweeted that Ground Zeroes is also not what is known as Project Ogre, another "open world" game on the FOX Engine.