There is absolutely no way to give you a complete answer to "What is the story behind Metal Gear" - the answer is just too big, having spawned an entire database of information across several games and its own Wiki online. However, I can summarize some of the primary game stories further down. Keep in mind that there are 11 different Metal Gear games (or is it 12 or 13? I can never remember).
Originally conceived by fictional Russian scientist Aleksandr Granin in 1964, Metal Gear is the name of a nuclear weapons armed, bipedal tank (it walks on 2 legs). It also has Gatling guns and other defenses for close battle action defense. It uses short and medium range nuclear missiles. There have been many Metal Gear versions across the game series.
The Metal Gear Universe is so large and intricately weaved by its creator, legendary video game master Hideo Kojima, that Metal Gear has its own Wiki on Wikipedia. Metal Gear is one of the most significant and influential video games ever developed, in that its storyline and gameplay have led to what we now consider to be the standard in action and stealth games. Before Metal Gear there had never been 'stealth' in any action game before, much less a 'Tactical Espionage Action' game in which the objective of the player doesn't involve killing everyone to obtain the goal. Kojima was the first to add a deep storyline to games, and as others caught on, it eventually led to other games being developed in a similar fashion. In time, such games and the gaming industry's adoption of movie-style production methods, led to the partnership with Hollywood and the movie industry using game stories as fodder for new movies. I would not be surprised to see a Metal Gear movie in the future (in fact Kojima has already agreed to a deal for one).
Kojima uses science and technology, both real and imagined, in the storyline. Cold War missions and spies, WWII spies, Supersoldiers developed and/or enhanced by cloning, genetic manipulation and nano technology, biological weapons, shadow governments and conspiracies, Bond-like gadgets, military research and revolts, media control, you name it - not much is left out of the MG world. What makes it cool is that a lot of it is based on many things in our history, and is told in such a way that it's believable. Much better than the standard "alien mutations gone amok" scenario of many games. Kojima strived for accuracy in every detail in the game, and as such sought out experts in the military, police and others referenced in the game to ensure that the player believes the scenario could be real.
Unlike a First Person Shooter though, the main character in the game uses only a tranquilizer gun and pistol to get through most of the game. While he can use enemy weapons and kill enemies, and CQC to immobilize, stealth action and NOT killing everyone is the biggest difference, as you get further and get more points for stealth tactics. Even a simple cardboard box is on the list of available resources. Shooting someone, making a loud enough noise or being discovered by any means will cause a host of security forces to bear down on you. Whether you survive depends on your own stealth tactics and skill, and ability to blend into the surroundings. Metal Gear 3 was revolutionary in the gaming industry by introducing adaptive camouflage suits to the game, and requiring Snake (in other words the player) to also survive by eating and drinking just like a real soldier would have to do in real circumstances. The player throughout the game must either find food or kill anything to survive - snakes, gators, birds, fish, etc. It also was a first in that it didn't follow the "corridor crawl" scenario of most games - the player can use whatever route needed to get to the objective. These kinds of innovations are Metal Gear and Kojima's real contributions to the gaming industry is that each game version, starting with the original Metal Gear, has presented the industry with new ideas and technology that with each game release has furthered the industry. Metal Gear is to console video games what Wolfenstein and Doom were to
original PC games.
In addition to Kojima's storylines and game vision, Metal Gear Chief Artist Yoji Shinkawa has designed some of the most striking art, both in game and out, ever seen in the gaming world (or anywhere else for that matter). His designs are a large part of Metal Gear's look and feel, and why the series stands out so much against other games that aspire to its creativity. Each game also has its own theme, reflections on major questions facing our society.
Key Characters (not all, just a couple of them)
The Boss - Code name female mentor of Naked Snake. Scar from Caesarean birth on her stomach resembles a snake. Knowingly and willingly battles Naked Snake and allows him to kill her in order to save her country and the world from nuclear devastation.
Big Boss - Code name given to a legendary soldier mentored by The Boss, he is considered the best of all time. His DNA is used to produce 3 clones:
Liquid Snake - Clone of Big Boss, Liquid has BB's dominant soldier genes.
Solid Snake - Clone twin of Liquid, Solid has BB's inferior (or recessive) soldier genes. Despite this however, Solid usually manages to find a way to beat Liquid in combat.
Solidus Snake - Clone of Big Boss, like both Solid and Liquid had accelerated aging written into his genetic makeup. However, since Solidus was cloned to replace Big Boss himself, he was created last, and his aging is more rapid because he's required to fill a role of an older man.
Otacon - Real name Hal Emmerich, provides tech support to the player's character in the game. Met Snake during the Shadow Moses Incident.
Liquid Ocelot - the fusion of the spirit of Liquid Snake and the body of Revolver Ocelot. Revolver Ocelot's arm was cut off by Gray Fox during the Shadow Moses Incident, and it was replaced with the arm of Liquid Snake. Later determined that the "spirit" of Liquid Snake wasn't actually involved.
Naked Snake - Former code name of Big Boss during his days as the disciple of The Boss.
In Galzburg, South Africa, a fortified country founded by a legendary mercenary in the 1980's, there is a fortress complex known as Outer Heaven. In 1995, the United States receives Intel that a WMD platform is being built within Outer Heaven. The U.S. government taps a high-tech, Special Forces team called FOXHOUND to infiltrate Outer Heaven. FOXHOUND is commanded by the greatest soldier who ever lived, the legendary Big Boss. He was to send in an agent to determine what was going on and neutralize any threat to the western world. FOXHOUND agent Gray Fox is sent and successfully infiltrates Outer Heaven, but contact is lost with him several days later. His final transmission contains only 2 words: "METAL GEAR".
After contact with Gray Fox is lost, Big Boss sends rookie operative Solid Snake, a clone of Big Boss, to follow Gray Fox, rescue him, find out more Intel on Outer Heaven and what the meaning of "Metal Gear" is. Successfully infiltrating Outer Heaven, he finds that Metal Gear (TX-55) is a huge nuclear armed bipedal tank, finds out that he has been lied to, and that the leader of the Outer Heaven fortress is none other than Big Boss himself. Forced to fight, Solid Snake defeats him, then applies explosives to Metal Gear TX-55 to destroy it. He then engages the self-destruct for Outer Heaven, and escapes before it is destroyed. This incident is known in the MG world as Operation Intrude N313.
While the original Metal Gear game is set in 1995, MGS takes place in the future, (now our past) in 2005. Game versions have taken place in the present, the future, and the past, relative to a game version's release date, further adding to the storyline. In this story, DARPA (Defense Advanced Research Projects Agency) is developing another Metal Gear known as REX at a Nuclear Weapons storage facility on Shadow Moses Island, in an island chain off of Alaska. A special forces group known as FOXHOUND (who work for the CIA and handle tactical espionage missions other Spec-Op units can't handle), led by Liquid Snake, a clone of the legendary soldier known as Big Boss, is there on a training mission during the testing of Metal Gear REX by the ArmsTech Corporation. Along with soldiers enhanced with special genes (Next-Gen or GENOME soldiers), Liquid Snake instead leads FOXHOUND in a revolt against the U.S and holds the DARPA Chief and ArmsTech Chief hostage.
FOXHOUND's demand is no less than the body of Big Boss, the greatest soldier who ever lived, killed at Outer Heaven in Operation Intrude N313. Using genes from Big Boss, they plan to enhance the GENOME soldiers to make them ultimate soldiers. Solid Snake, now a retired ex-FOXHOUND unit member and Liquid Snake's clone twin, is sent to infiltrate the facility on Shadow Moses Island. His mission is to rescue the DARPA and ArmsTech guys, determine if FOXHOUND is capable of launching a nuclear missile as they have threatened, and if so, stop them.
Note: This basic plotline is central to all the MG games for the most part, but each game has its own twists and turns that make them truly individual.
Solid Snake, arguably one of the coolest (if not THE coolest) game characters ever created, successfully infiltrates the Shadow Moses facility. Telling you more would spoil the game should you decide to play it. Suffice it to say that Snake finds out that not all is as it seems.
The entire episode in Metal Gear Solid is known in the MG world as the Shadow Moses Incident.
MGS 2 has 2 parts, the "Tanker" mission at the beginning with Solid Snake, and the "Outer Shell" mission with a new FOXHOUND operative named Raiden. The introduction of Raiden as the main character caused a negative backlash from dedicated fans (myself included), as Raiden just ain't Snake. Snake appears later in the mission, but has his own objectives and is more of an advisor to Raiden.
Ocelot boards RAY, but his arm begins to have spasms and he begins to speak in Liquid Snake's voice (the reason for this is given later). He escapes with RAY, and the tanker sinks, apparently killing the Marine Commandant, the head of the mercenary unit, and Solid Snake. A massive oil spill ensues polluting New York Harbor, and Snake is blamed for the whole incident.
Making his way around, Raiden finds the bodies of Seal Team 10, originally sent to take over the facility and rescue the President, but failed. Encountering the team's killer, Dead Cell member Vamp, he is rescued by Seal Team 10 survivor "Iroqouis Pliskin", who saves Raiden and gives him his first weapon, a SOCOM pistol. Pliskin is later revealed to be none other than Solid Snake, who faked his own death by substituting Liquid Snake's body for his own. Being clones and genetically identical to each other, forensic examiners had no way of knowing it was Liquid's and not Solid Snake's body.
Note: The name "Pliskin" is from a character played by actor Kurt Russel in the movies "Escape from New York" and "Escape from LA". His character's name is "Snake Pliskin".
It's also learned that Otacon's step-sister Emma Emmerich, who he hasn't spoken to in many years, is a computer programmer aboard the Big Shell. We also find out about The Patriots, the shadow group in real control of the country, who even decide who's going to be the next president (I thought it was the media - silly me). The President asks Raiden to rescue Emma and ask her to eradicate the Artificial Intelligence known as GW, which is going to be used by The Patriots to control the country.
Note: Anyone under direct control of the Patriots have nanomachines in their bodies that force them to say "La Li Lu Le Lo" (pronounced Lah Lee Loo Lay Low) whenever they tried to speak the word "Patriots" in order to keep them secret. I mention it because it turns up occasionally in popular culture.
As events progress, the appearance of Metal Gear RAY shocks Raiden, but he doesn't know the real truth until later - Big Shell was merely a cover facility for the development of Arsenal Gear, a gigantic underwater mobile fortress that uses remotely operated, pilotless Metal Gear RAY's for its own defense.
Although not labled a "prequel" per se, MGS3 takes place during the Cold War in the '60's, set in a time period before the previous MG games. As I said previously, MGS3 is revolutionary in that it had multiple avenues of getting to an objective, the introduction of adaptive camouflage for Snake's suit, the requirement that Snake must eat during the game to survive or his energy would drop (and eventually he would die if not replenished). His meals could be anything a soldier in the field would normally subsist on - man made food or animals/fruits/vegetables found in the wild. Close Quarters Combat (CQC) is also introduced in MGS3. Unlike the previous games, this one features Naked Snake as the main character, and his mission to find and assassinate his longtime mentor, The Boss. Unbeknownst to Snake, The Boss has information he doesn't, and she realizes that due to circumstances beyond her control she must knowingly and willingly give her life for her country and the sake of the world by allowing her disciple to kill her in battle using the CQC tactics they developed.
MGS3 shows Naked Snake (aka "Big Boss" in previous MGS games) to be the good guy equivalent of Solid Snake, rather than the antagonist he portrays in the earlier games. MGS3 shows what changed him, introduces the characters that are prominent in the earlier games, those that lead to the creation of Solid, Liquid and Solidus, the history behind the Patriots, etc. Kojima at the time believed that MGS3 would be his last MG game, and it's obvious he's trying to cover the history and explain plot and storylines in the MG universe to this point. Fortunately for us, it wasn't his last. MGS3 by far had the best gameplay of all the games to that point.
MGS4 is the one that ties everything in the Metal Gear world together. All questions are answered, old characters are brought back, things that didn't seem to make sense in other games are now shown to be a genius of plot and storytelling - all this plus the pre-eminent release of the game on the PS3. The graphics and gameplay are unbelievable. True to form, Kojima persisted in bringing back an old friend that wasn't released with the PS3 contoller - the Dual-Shock vibration feature. Dual-Shock was removed in order to allow the insertion and development of the "Six-Axis" feature, which in this gamer's viewpoint is a a monumental failure and absolute waste of gaming resources. It's frankly just a pain in the a$$. Sony doesn't make mistakes often, but the Six-Axis feature is one of them. That Kojima successfully lobbied and used his clout to bring back the Dual-Shock controller is a major achievement
indeed. Games just didn't seem the same without it.
Set in the future in 2014, 5 years after the Big Shell incident in MGS2, the focus is on the role of Private Military Companies/Contractors (PMC's) in fighting battles on foreign soil. Nano technology is widely used to enhance and control PMC soldiers. The biggest PMC's are controlled by Liquid Ocelot. Ocelot plans to launch a military strike to gain control of the nanomachine system known as the "Sons of the Patriots" (SOP). The mother company which owns the largest PMC's,and controlled by Liquid Ocelot, is known as Outer Heaven - sound familiar? Having put together an army big enough to rival the U.S. Solid Snake, now aged by his genetic alteration that included accelerated aging, is tapped by Colonel Roy Campbell, Solid's closest friend and the former Executive Officer of FOXHOUND who is now working for the United Nations, to enter the Middle East and terminate Ocelot. Snake meets up with Meryl Silverburg, who is now leading a team of her own and is there to investigate the PMC's activities, not knowing she's working for Campbell, who in reality is her father. Her team is codenamed "RAT PATROL ZERO-ONE" - when their initials are arranged, (RAT PT 01) the resulting anagram spells out "PATRI0T".
In order to get to Ocelot, Snake must fight and destroy the Beauty and the Beast unit, comprised of Crying Wolf, Raging Raven, Screaming Mantis and Laughing Octopus. Their names are references to the members of FOXHOUND from MGS, their emotions from The Boss's Cobra Unit in MGS3, and weapons from members of Dead Cell of MGS2. All members are female who have suffered PTSD (Post Traumatic Stress Disorder) from incidents when they were growing up in war zones, and witnessed or were forced to committ atrocities on friends and family.
Snake is assisted by a mysterious soldier who later turns out to be Raiden, who has been apparently missing since the Manhattan Incident in MGS2. Having had many body parts replaced with cybernetic implants, he has impressive enhanced abilities.
MGS4 also returns to Shadow Moses, where Snake finds the wrecked (but salvageable) remains of Metal Gear REX. Surrounded by robot sentries called Geckos, Otacon manages to reactivate REX while Snake holds off the Geckos, who are increasing in number very rapidly. With REX's armament at his disposal, he fights his way out of the Shadow Moses underground maintenance facility to the dock facility, only to meet Liquid Ocelot who is piloting another Metal Gear. Snake also finds out that Ocelot has a new Arsenal Gear class ship called "outer Haven". Outer Haven is an Arsenal Gear class battleship that has been hidden at Shadow Moses and is capable of submerged operations. Having removed the Rail Gun launcher from REX (the Rail Gun can launch a nuclear warhead without using a rocket, making it a stealth launcher) and mounting it on Outer Haven, makes it a significant threat to the world. Additionally, Outer Haven is fitted with Octo-Camo (the new adaptive camoflage technology introduced in MGS4 in the suit Snake wears), meaning it can be virtually invisible. It also houses the GW Artificial Intelligence server from the original Arsenal Gear from MGS2. Although Emma Emmerich was successful in uploading a virus designed to destroy it, it only shut it down.
After successfully getting aboard Outer Haven (the plan is to destroy the Rail Gun) Snake fights his way through the Beauty and Beast team, shuts down GW, and fights Ocelot in a CQC battle, the outcome determined by the player. If successful, in the end and near death himself, Solid Snake is seen in graveyard where Big Boss (aka Naked Snake) is buried. However, he is shocked when Big Boss shows up at the cemetery alive. The remaining cutscene explains in detail exactly how this has come to pass, further tying up loose threads in the storyline.
One of the more touching plotlines is tied up with Raiden being reunited with his former girlfriend, who assisted him as a tech during MGS2 (Rosemary). Thought to have lost their baby, and then married Colonel Campbell (alienating his daughter Meryl Silverburg as a result), it is learned that their "marriage" was a fake to keep the Patriots from targeting Rosemary and her child, who she in fact gave birth to. It is one of the better story tie-ups in the game.
Metal Gear is one of those games that players either love it or hate it - it's that simple. I was hooked the moment I started playing, so my bias is obvious. But it's not just the gameplay - everything in the games, the artwork, storyline, plot twists, parallels to our own culture, themes that are important given today's challenges, everything is brought together by Kojima in one huge masterpiece spanning many games.
I've told you the backstories to the main Metal Gear episodes, but to really go deeper and learn more detail you either need to download the Metal Gear Add-On Database from the PlayStation Store (it's free), go to the Metal Gear Wiki, or get the games and spend hundreds of hours immersed in the Metal Gear world that Hideo Kojima has created like I and thousands of others have over the years. Hopefully I've given you enough here that you'll want to get into the game for yourself and find out what I and others already know - Metal Gear is by far one of the best games ever created.
Metal Gear Wiki
Metal Gear Database Add-on
Metal Gear Solid
Metal Gear 2: Sons of Liberty
Metal Gear 3: Snake Eater
Metal Gear 4: Guns of the Patriots Special Edition
Hundreds of hours of Metal Gear gameplay
Note: Merely stating that the Metal Gear story is about "A guy named Snake who infiltrates a warehouse to destroy Metal Gear" is just an insult to one of the greatest games ever conceived, and one that has had a profound influence on the gaming industry as a whole.
P.S. The entire backstory can also be downloaded from the PlayStation Network (Metal Gear Solid 4 database) on the PlayStation 3.
Metal Gear is about a guy named Snake who must infiltrate a warehouse to destroy Metal Gear. A warmachine which could end the Cold War, and make it quite hot.