That’s a difficult question. Metal Gear is a game series that has been going for several years and has come out on several platforms. One can discuss its evolution technologically, plot-wise, or from a gaming perspective. I’m going to do so plot-wise, and occasionally from a gaming perspective.
TL;DR: don’t start MGS V: Phantom Pain if you haven’t played the previous games. There’s a special collection called the Metal Gear Solid: The Legacy Collection, which has all the games on a single disk, so you can just buy that and play everything. If you don’t feel like doing so either, read the Wikipedia summaries of the plots of each game before starting Phantom Pain.
Metal Gear and Metal Gear 2: Solid Snake
Plot-wise, each game is basically this: Snake, an SF-soldier, has been sent on a mission to infiltrate a base where the enemy (whatever he may be) has built a tank capable of launching nuclear missiles. Snake is to take it out and with it, the party that responsible for the insurrection.
Typical for Metal Gear games is the long cinematic cutscenes, making it appear as if the game is more movie than a game. Metal Gear Solid IV, for example, has more cutscenes than gameplay, and people have compiled all the cutscenes into whole ‘movies’ of several hours (look for them on YouTube).
Another typical quirk of Metal Gear is its Japanophilia, the off-beat humor, and its sense of realism. It doesn’t treat the military as some sort of corrupt organization, devoid of morality and intelligence, but as an organization that used for political goals, as is the case in the real world. It allows you to peak into the logic of international affairs, technology, and political philosophy. Not too much though, since it’s still a video game and not a tool of education.
The series of Metal Gear started years ago, with the game ‘Metal Gear’ in 1987. In that game, a terrorist called whose identity is unknown has built a nuclear-equipped tank called ‘Metal Gear’, designed by a man called Dr. Pettrovich Madnar, and a rookie of the fictional special forces unit ‘FOXHOUND’, code-named Snake, is sent in to take the leader of the insurrection and the Metal Gear out.
He succeeds in doing so with the help of Big Boss, who turns out to be the leader of the insurrection in the first place. Snake kills both him and destroys the Metal Gear, and world peace is preserved.
In the process of infiltration, Snake frees a called Grey Fox, or Frank Jaeger (that’s his real name), who was the FOXHOUND man sent in before Snake, but with whom they lost contact. In the process of infiltration, Snake has to defeat each one of the members of the insurrection, all of which have special abilities.
Snake defeating terrorists with special powers recurs in every game, and they form the ‘bosses’ of the game.
In Metal Gear: Solid Snake, Big Boss returns with a new Metal Gear, and Snake is sent out once more to destroy Metal Gear and kill Big Boss. In the process however, Frank Jaeger is killed.\
Both Metal Gear games were an overhead gameplay, like on a Gameboy. They were among the first real stealth games, and have laid out the foundations for modern stealth games.
Metal Gear Solid
Years later, a new game is released, Metal Gear Solid (1998). This game is about a new Metal Gear that has been built on the basis of Shadow Moses on one of the islands on Alaska. But the Metal Gear, Metal Gear Rex, was seized by FOXHOUND units aided by vagabond Russian mercenaries. The terrorist leader calls himself Liquid.
The liquid is aided in this process by Revolver Ocelot, a man that recurs in almost all the series. Another terrorist here is Sniper Wolf, a voluptuous woman who is an excellent sniper.
Snake hiding from Russian mercenaries on Shadow Moses
The snake comes across Otacon, the man who designed the new Metal Gear, and Liquid as well. Liquid reveals that both he and Snake were actually clones of Big Boss. Liquid, however, got all the recessive genes, and he is, as a result, the unstable one of the two.
This cloning project of Big Boss, which took place without his consent, is called the ‘Les Enfants Terribles’ project.
Snake also meets Meryl, the daughter of his commander, Colonel Campbell.
While infiltrating Shadow Moses, Snake meets a strange ninja, that is seemingly undefeatable, but also suffers from aggressive seizures. The ninja even comes to Snake’s help while fighting Ocelot, and cuts off the arm of the latter.
It is later revealed that the Ninja, who goes by the name ‘Deepthroat’, is actually Grey Fox. One of the members of Snake’s support team, Naomi, is Grey Fox’s younger adoptive sister. She blames Snake for what happened to Grey Fox and how he has to live now.
But all of that doesn’t matter, for Liquid manages to unlock the keycodes to Metal Gear and uses it to kill Grey Fox. Snake manages to destroy Metal Gear Rex, but he is not capable of killing Liquid, for he is just as tough as he is.
Snake fights Metal Gear Rex
Snake is then however aided by something he didn’t know he was carrying: a virus called FOXDIE. In his infiltration of Shadow Moses, Snake meets several extraordinary individuals all of whom seem to die of a heart attack.
Snake finds out he was infected with a virus called FOXDIE so that anyone who knew anything about Rex was killed, but didn’t harm other people whose genes didn’t match the virus’ receptors. Remember this, for it comes back later. And so, after a long battle with Liquid, Liquid is killed not by Snake, but suddenly gets a heart attack, and dies of FOXDIE.
Metal Gear Solid was the first real 3D Metal Gear game, but still had a overhead view. Nevertheless its graphics were extraordinary for the time, and its plot was relatively deep for games at the time.
Though Snake managed to destroy Rex, the technology is partially leaked and other Rex’s start to appear.
As a result, the US military starts to develop Metal Gear Ray, a Metal Gear that was designed specifically for destroying Metal Gear Rex.
At the end of Metal Gear Solid, a new US president George Sears is inaugurated, who finds out that the US government, and the rest of the world, is being controlled by a secret organization called ‘The Patriots.
Metal Gear Solid 2: Sons of Liberty
Five years after Shadow Moses, Metal Gear 2: Sons of Liberty starts. Snake, who left the US military, has started to work with Ocelot to hunt down Metal Gears around the world. They come across Metal Gear Ray, and they hear that it is being transported for the bay of Manhattan.
Snake infiltrates to take pictures of Metal Gear Ray but does so at the same time as vagabond Russian soldiers who want to restore their homeland. They are lead by Revolver Ocelot, who, in the end, betrays everyone and steals Metal Gear Ray himself and destroys the ship.
Ocelot has taken on Liquid’s arm to replace his own, but when seeing Snake Liquid’s nanomachines take over in a wild seizure and Liquid tries to kill Snake. He fails to do so, but Snake disappears.
Metal Gear Ray
Sometime later, an oil plant off the coast of Manhattan has been seized by anti-terror training unit Dead Cell and others (one of the others being Revolver Ocelot), and a young SF rookie called Raiden is sent in to stop them from causing a major environmental disaster.
But the plot was but a ruse, meant to distract the public from what was really happened. The former US president, George Sears, who now goes by the name of Solidus (a third clone of Big Boss, which was considered a ‘perfect’ clone of Big Boss because it had exactly the same genome), seized the plant to gain control of Arsenal Gear, a massive secret underwater facility that is protected by Metal Gear Rays and is meant to filter global information.
Arsenal Gear is thus, a giant A.I. It is through Arsenal Gear that the Patriots control the world. Solidus wishes to destroy Arsenal Gear, and Raiden, a former child soldier from Liberia, was sent in to stop him.
But once he finds out what is happening, he isn’t sure what side to choose. He is aided by Snake, who was presumed dead. His commander, Col. Campbell, turned out to be Arsenal Gear imitating the real Col. Campbell, and Raiden was used both to take out Solidus and his men, as well as setting up the right scenario to transform any soldier into a ‘Solid Snake’, so it can be used as a training program to produce soldiers as capable as Snake.
Otacon (real name is Hal Emmerich) discovers that his younger sister had been taken captive by the Patriots and was forced to work for them as a programmer on Arsenal Gear. But this allowed her to develop a worm called FOXALIVE, which would destroy Arsenal Gear once uploaded.
But Revolver Ocelot goes rogue once more, and betrays Solidus, and crashes Arsenal Gear in New York. Raiden uploads FOXALIVE manages to kill Solidus, and Snake goes after Liquid Ocelot (as we call him now), and Raiden contemplates how to continue on from now on, knowing that the world is controlled by the Patriots.
Metal Gear Solid 3: Snake Eater
The next game is considered the best until MGSV: Phantom Pain came along (EDIT: I’ve now seen enough of MGSV to still consider MGS3 personally the best MGS).
It’s Metal Gear Solid: Snake Eater (or MGS3), and isn’t about Solid Snake, but about Big Boss. Remember that Snake and Big Boss look alike since Solid is a clone of Big Boss, but Big Boss is not Solid Snake. Big Boss is also the main character of MGSV: Phantom Pain.
From left to right: Liquid, Big Boss, Snake
Snake Eater takes place in 1964, and is all about the Cold War. Jack (later Big Boss), a Green Beret operative assigned to the CIA, then confusingly codenamed Naked Snake (Snake for short) infiltrates Russia to take out the Shagohod, a Soviet nuclear-equipped tank, and a Russian colonel Volgin.
Volgin planned to mass-produce the Shagohod, ship it all around the world and to overthrow the Soviet government. But that takes money. Where did he get the money?
As it turns out, after WWII, the leaders of the three greatest nations, the Soviet Union, the US and China came together and amassed funds to fight the war five times over.
The people in charge of this were called the Philosophers, and their big pile of money was called the Philosopher’s legacy. Volgin’s father managed to get a hold of the Philosopher’s Legacy, and Volgin inherited it from him. These are the funds he uses to pay for his forces, his fortress, and the development and planned mass-production of the Shagohod.
The designer of the Shagohod was the rocket scientist Sokolov. Sokolov and his family had defected to the West years earlier, but he was sent back in a deal between the USA and the Soviet Union to resolve the Cuban missile crisis. Snake was sent on a mission codenamed ‘Virtuous Mission’ to retrieve Sokolov once more.
He was stopped by his mentor, The Boss (a WWII hero), and her former SF unit called the Cobra Unit. The Boss explains she is defecting to the Soviet Union, and along with Sokolov she is taking two nuclear Davy Crocket missiles with her as a gift for Volgin. She breaks Snake’s arm and throws him off a bridge, but he survives. What happened next, however, was unplanned.
Volgin, in an act of sadism, used one of the Davy Crocket missiles to blow up a military research facility a rival Russian faction was working on. This nuclear explosion and the exfiltration is discovered by the Soviet authorities, and the USA is forced to explain that the Boss defected to Volgin.
Volgin plans to overthrow the Soviet government with his new weapons, and so the Soviets give the US a choice: fix our problems, or we will start a nuclear war, for we will hold you responsible for the nuking of our country.
And so Snake is sent once more into Russia with a new mission: kill the Boss, destroy the Shagohod, and kill Volgin. That’s operation Snake Eater and is the main story of the game.
Snake Eater is considered the best game because of many reasons: it had the best plot, it had camouflage, the best characters, and some of the coolest bosses.
Snake manages to defeat the Cobra Unit, but is unable to kill a young Soviet Major that’s under Volgins banner: a major called ‘Ocelot’. Ocelot discovers, thanks to his run-ins with Big Boss, his natural preference for revolvers and switches to using Single Action Army revolvers for the rest of his life.
Big Boss is aided in this mission by a spy the Soviets send to help him take down Volgin: ADAM and EVA, though ADAM fails to show up. EVA turns out (at the end of the game) to be a spy sent by the Chinese to capture the Philosopher’s Legacy.
But she fell in love with Snake, and her infiltration as ‘Tatiana’, a woman who serves as the mistress of Volgin, was quickly discovered by The Boss. But the Boss didn’t reveal her secret mission to Volgin or anyone else and allowed EVA to continue her mission.
Just a quick sidenote: the Philosopher’s Legacy isn’t a big pile of gold physically – it’s actually a small disk containing the information of all the bank accounts around the world into which that money has been deposited. Whoever has that chip, knows where the money is.
At the end of the game, it is revealed that Ocelot was actually ADAM, and that EVA only managed to get a fake chip, for the real Legacy was with Ocelot, who served as a double agent for the Americans.
During this operation Snake’s commander was major Zero. Zero ended up with the Philosopher’s Legacy and founded The Patriots, as a successor to the Philosophers. The Patriots are also known as Cipher, and after an ideological falling out with Big Boss after the mission Snake leaves the US military and the USA, finding a place to be out of reach of the Patriots.
Metal Gear Solid: Peace Walker
The next game in line is Metal Gear Peace Walker, which is my least favorite MGS game. In this game, Snake got together with a man called Benedict Kazuhira ‘Kaz’ Miller and they founded an organization called Militaires Sans Frontières, which is a paramilitary organization which acts as mercenaries.
Its real goal is to make a place that isn’t in control of Cipher, which at this point is just growing and struggling to control the US. In the year 1974, they are hired by the KGB to help them establish a socialist stronghold in Central America. In the process, he is aided by Paz, a Costan Rican native girl, and Chico, a Nicaraguan native who fell in love with Paz later on in the game. The KGB helps them establish a base for their own, dubbed ‘Mother Base’, which is a former oil platform turned into a military stronghold.
Snake discovers the existence of a nuclear tank called ‘Peace Walker’, and destroys it before it can be used. But another metal gear, ZEKE, was built aimed to deter the MSF of Snake, and this one was seized by the young girl Paz, who reveals herself to be an agent of Cipher.
He is to surrender the MSF to Cipher, or else she will fire a nuclear missile at the USA, which will brand the MSF as nuclear terrorists. Snake manages to cripple ZEKE before Paz can use the missile, and Paz herself is thrown into the ocean. Snake accepts the title of ‘Big Boss’ and proclaims they are living in ‘Outer Heaven’, for they truly are out of reach of Cipher.
The game didn’t feature anything new gameplay wise, with the exception of base building. It’s my least favorite, since it used more comic book style animations for scenes, instead of actual moving models.
Chronologically, the next game is Ground Zeroes, but the next one that was actually released was Metal Gear Solid IV: Guns of the Patriots. That last game is more movie than game, and it’s also one of the more complicated games plotwise. I postpone it for now, and first deal with Ground Zeroes.
Metal Gear Solid V: Ground Zeroes
In Ground Zeroes it is revealed that Paz survived, and she was captured and brought to Camp Omega (Guántanamo Bay). Chico tried to save her, but got captured as well. In the meantime, the IAEA announces that it wants to investigate Mother Base because they were rumored to have nuclear weapons (which they did, they had ZEKE).
Big Boss came across Dr. Huey Emmerich in the Peace Walker game, who was the designer of ZEKE and father of Hal ‘Otacon’ Emmerich. He helps Big Boss to clean Mother Base and make it appear as if the MSF didn’t have any nuclear weapons (ZEKE is hidden on the bottom of the sea).
But when Big Boss hears that Paz and Chico have been captured, he must act quickly to make sure Paz or Chico don’t spill any secrets on ZEKE or the Peace Walker Incident. And so, hours before the UN inspection of Mother Base, Big Boss infiltrates Camp Omega to save Chico and Paz.
Snake succeeds in doing so but finds out Paz was tortured by a man named ‘Skullface’, a man whose face was physically burned in WW2 in Hungary and now is without a doubt, one of the evilest men on the planet. Skullface’s identity is, for now, unknown, and more light is shed on him in MGSV.
As Big Boss returns to Mother base to interrogate Paz and Chico he sees that Mother Base is under attack. He manages to save Miller and some comrades from its complete destruction, and Miller reveals that the UN inspection was but a sham, a cover-up to destroy the MSF.
Miller, in his rage, blames it on Paz and thinks she told essential information to her interrogators that led to this attack. Paz, who until then was more or less conscience, wakes up and reveals that her interrogators have put a bomb inside here. She throws herself out of the helicopter, but it is too late: the bomb explodes, and she takes down the helicopter with here.
Big Boss survives, but ends up in a coma. Miller loses an arm and a leg, and many comrades are lost as well. This is where the Phantom Pain starts.
I want to go into more detail on the Les Enfants Terribles project.
Big Boss was present at the nuclear bomb testing at Bikini Atoll, and was as a result rendered infertile. But Big Boss’ genes were considered too important to let them disappear in the pages of history by Major Zero, and thus he led a project, together with Dr. Clark (who was one of the support members of the team on operation Snake Eater and Virtuous Mission in the 60’s) to clone Big Boss.
EVA offered herself as the surrogate mother, and she gave birth to David (Solid Snake) and Eli (Liquid Snake). When Big Boss found out, he left in disgust with the project, and Zero went into hiding.
When Big Boss is later defeated by Solid Snake in the Outer Heaven uprising (Metal Gear 2), his body is recovered by the Patriots, and induced in an artificial coma using nanomachines. His genome is used to produce Next-Gen soldiers for the Patriots, which will be used to counter both Snake and Liquid Ocelot.
Snake, Otacon, and the real Colonel Campbell discover later that that only part of the Patriots system was shut down by the worm Emma made, a part called GW (George Washington). In order to take down the entire system, you need to take down JD (John Doe), a satellite orbiting earth in space.
Liquid Ocelot plans to do take it down using a nuke and create total anarchy. So while both Ocelot and Snake oppose the dictatorship of the Patriots (of Zero), Ocelot plans to create anarchy from which new systems will rise, while Snake and the like want to see the bureaucracies kept in place but the Patriots out of the picture.
By the time Metal Gear Solid IV: Guns of the Patriots (released 2008, takes place in 2014) comes along, it’s clear that there are a couple of things wrong with Snake’s (=David, not Big Boss) body. First off, the virus, FOXDIE, Snake was carrying with him, is mutating. The virus’ receptors are breaking down. As a result, in time the virus will kill everyone, not just the people it was designed to kill years ago at Shadow Moses.
Snake is thus becoming a walking biological weapon. Another thing is that Solid Snake is aging far too rapid for his age. He looks as if he is in his 60s, even though he should be somewhere in his late 30s. This is because his genome was modified so he would naturally grow old fast, in order to keep Snake under control, making it impossible for him to continue rocking like Big Boss would.
Snake is thus forced to on a last mission: he is to take down Ocelot, and to prevent himself from becoming a biological weapon. Since there is no way to kill the virus in his body, he is left no other choice but to commit suicide after his mission is over. This is the plot of Metal Gear Solid IV: Guns of the Patriots. I won’t spoil it any further, and I suggest you watch videos on YouTube for the real deal.
Hope that explained most of the plot for you. If you have any questions, ask away in the comments.