Retcon

Retroactive continuity, or retcon for short, is a new piece of information that imposes a different interpretation on previously described events. In regards to the, a retcon is a situation in which the storyline of a new game explains or changes an event from a previous one, or attaches a new significance to it.

Retcons are typically used in the Metal Gear series to facilitate a dramatic plot shift or account for an inconsistency. Some retcons add information that contradicts the information that was previously established, while others instead fill in missing background details, allowing the accommodation of prequels/sequels or acknowledgement of real world developments. While creating the series, Hideo Kojima was willing to contradict established continuity on occasion, in order to ensure that "new games are as good as they can be."

Metal Gear 2: Solid Snake

 * It is revealed that the game takes place in 1999, three years after the events of Metal Gear. In the original game and its manual, the year of its setting was unspecified (19XX).


 * Kyle Schneider survived the events of Metal Gear and is revealed to have become a Zanzibar Land mercenary.


 * Schneider explains that NATO destroyed Outer Heaven through a bombing campaign that was conducted following Snake's escape. This contradicts both the ending of Metal Gear and the summary of that game's events in the Metal Gear 2 manual, which heavily imply that Outer Heaven was destroyed by a nuclear explosion that was activated as a result of the self-destruct sequence initiated by Big Boss.


 * Dr. Pettrovich's name is changed to Dr. Petrovich Madnar.


 * Gray Fox reveals that he and Snake were friendly rivals while training together as FOXHOUND operatives. In Metal Gear, Fox's dialogue suggests that their first meeting was Snake's rescuing of him.

Metal Gear Solid

 * Solid Snake is depicted as an American of Japanese descent, and an operative of the U.S. Army special forces unit FOXHOUND. He was previously described as being a Japanese-British operative of the NATO-led FOXHOUND in the Metal Gear 2 user's manual.


 * Not in the game itself, but the manual for the game reveals that Big Boss had actually been the founder of FOXHOUND, instead of nominated as commander as previously indicated in the Metal Gear 2 manual. This retcon was furthered in Metal Gear Solid 3.


 * The manual also states that Snake's IQ is 180. In the Metal Gear 2 manual, this figure was 160.


 * The global setting during the Zanzibar Land Disturbance is given a different context that mirrors real world developments since the release of Metal Gear 2: nuclear weapons were not completely abandoned in the late 1990s; the Soviet Union and Communist Bloc collapsed as they did in real life; the Commonwealth of Independent States (CIS) forces, formed around Russia, fought Zanzibar Land in the Mercenary War, rather than interventions from both East and West; Gustava Heffner was a former member of the Czech Secret Police rather than an active one.


 * The manual for Metal Gear 2 states that Operation Intrude F014 takes place in 1999. The Previous Operations summary, as well as subsequent sources, states that the game takes place four years after the events of Metal Gear. This contradicts Metal Gear 2, where Dr. Madnar, Snake, and George Kasler state that three years had passed since the events of Metal Gear. This was due to the manual stating that the Outer Heaven Uprising began in 1995, while TX-55 Metal Gear was developed a year later.


 * Snake states that Big Boss had informed him that he was his father. This revelation was never featured in the previous games.


 * Gray Fox is now the only FOXHOUND member to have ever attained the "Fox" title. It was previously stated that he was the last one to have done so under Big Boss's command. In addition, it is revealed that he survived the events of Metal Gear 2 and was turned into a cyborg. It was heavily implied in the previous game that Fox died after fighting Snake.


 * When Snake discusses Gray Fox with Naomi Hunter, he states that "[he] learned a lot from him" and "he showed [him] the ropes" during the Outer Heaven Uprising. In Metal Gear, the liberated Fox simply tells Snake what Metal Gear is and where Dr. Madnar is located within Outer Heaven (with his directions turning out to be incorrect due to Madnar being moved just before Snake arrives at the location). Fox is neither seen nor mentioned again for the rest of the game.


 * Master Miller is depicted as a Caucasian with blond hair. He was originally depicted as Asian and with black hair.

Metal Gear Solid 2: Sons of Liberty

 * Adding to the retcon established in Metal Gear Solid regarding the plotline in Metal Gear 2 about nuclear weapons being completely dismantled, a speech given by Scott Dolph during the Tanker Chapter establishes that then-President George Sears (Solidus Snake) had pushed for the NMD program to be completed, and the Plant Chapter also accredited James Johnson for its further success, and even the development of a purified hydrogen bomb.


 * It is revealed that Sergei Gurlukovich was leading a private mercenary group during the events of Metal Gear Solid. Sergei was previously described as the "head of Spetsnaz."


 * Although not in the main game itself, Nastasha Romanenko's novel In the Darkness of Shadow Moses: The Unofficial Truth reveals that the Patriots had actually been responsible for Jim Houseman's arrest, something that Roy Campbell had previously been attributed to.


 * At the end of Metal Gear Solid, it is implied that FOXDIE would kill Solid Snake soon after the game's events. In this game, it's revealed that this isn't the case, with supplementary material from In the Darkness of Shadow Moses explaining that the activation date was set to a wildcard value.

Metal Gear Solid 3: Snake Eater

 * The loss of Big Boss's eye occurs during the game, which is set in 1964, rather than the late 1980s, as previously claimed in the Metal Gear 2 user's manual. The injury did not force him to retire from the frontline, as it did in the former account.


 * Big Boss's sterility was established to have been caused by radiation from nuclear testing on the Marshall Islands. Earlier sources, including the Japanese version of Metal Gear Solid, simply stated that he had become sterile due to injuries sustained in direct combat.


 * Not in Metal Gear Solid 3 itself, but the ports for Metal Gear and Metal Gear 2 included in Metal Gear Solid 3: Subsistence changed the names of several characters in the games. In addition, all the character portraits were given new and/or updated designs by Yoji Shinkawa in the latter to replace the dubiously-legal use of digitized photographs of famous Hollywood actors.


 * Otacon's claim that he developed Metal Gear REX after being inspired by his "Japanese animes" is somewhat contradicted by the revelation that Aleksandr Leonovitch Granin had an identical design decades earlier, which was forwarded to Otacon's father, Huey Emmerich. Unless he is supposed to have independently created the exact same design by pure coincidence, it is not particularly clear what Otacon's input on the project is supposed to have been.


 * The blueprints for Granin's Metal Gear concept has a rail gun on one of them. In Metal Gear 2, it was mentioned that rail gun technology was being developed in the 1990s. Furthermore, in Metal Gear Solid, Otacon specifically mentioned that the technology had first been developed as part of the SDI initiative during the 1980s before problems caused it to be shut down.
 * This sequence also manages a retcon in a different series entirely by implying that Jehuty from Zone of the Enders was designed by Granin in the 1960s rather than Rikoah Hardiman sometime in the 22nd century.


 * The ending timeline states that FOXHOUND was founded in 1971, while the Metal Gear 2 and Metal Gear Solid manuals had earlier stated that it was founded during the 1990s. This retcon apparently had been a last minute addition, as the leaked Metal Gear Solid 3 voice casting sheet mentioned that FOXHOUND was founded in the 1990s. Big Boss's motivation for founding FOXHOUND was changed from the Metal Gear Solid manual's account, revealing that he formed it to replace the FOX Unit, rather than his being impressed with the effectiveness of high-tech weaponry during the Gulf War.
 * Donald Anderson is revealed to have once been a part of Big Boss' support team, under the name "SIGINT." This is strongly implied in 3's ending (in that he joined ARPA, while he is the "DARPA Chief" in MGS) and stated plainly in MGS4.

Metal Gear Solid: Portable Ops

 * Frank Jaeger's past is retconned, adding in another confrontation between him and Big Boss in Mozambique, detailing his involvement in the San Hieronymo Incident. In addition, Jaeger was previously referred to as a child soldier by Naomi Hunter in Nastasha Romanenko's book when describing how he adopted her in the 1980s, but he is a teenager in Portable Ops.


 * Nikolai Stephanovich Sokolov's apparent death during Operation Snake Eater is expunged, having instead survived with the aid a fake death pill from The Boss.


 * Gene claims that a CIA strategist had deliberately manipulated Colonel Volgin into launching the Davy Crockett in Tselinoyarsk, thus ensuring The Boss's self-sacrifice.


 * It is shown that both Metal Gear RAXA and the Intercontinental Ballistic Metal Gear preceded TX-55 Metal Gear.


 * The Patriots usurp power away from the American branch of the Philosophers. In the ending timeline of Metal Gear Solid 3, it was stated that the Patriots were a direct continuation of the American Philosophers under a different name.

Metal Gear Solid 4: Guns of the Patriots

 * Para-Medic is revealed to be Dr. Clark, the person responsible for Gray Fox's cybernetic augmentation, despite being referred to as a male in Metal Gear Solid.


 * EVA is revealed to be the surrogate mother of Solid and Liquid Snake.


 * Solid Snake's Japanese ancestry is explained to be a result of the donor eggs that were used in the Les Enfants Terribles project coming from Dr. Clark's assistant.


 * The founders of the Patriots are revealed to be Naked Snake's support team from Operation Snake Eater and Ocelot.


 * Dr. Madnar survived the events of Metal Gear 2 and is revealed to have been living in Eastern Europe, whereas previous sources implied that Solid Snake had killed him.


 * Big Boss also survived the events of Metal Gear 2 and is revealed to have been placed in a nanomachine-induced coma for 15 years and put back together from pieces of Solidus and Liquid Snake's corpses. Previous games had explicitly stated that Big Boss was killed during his fight with Solid Snake.


 * Solidus Snake is revealed to have survived his fight with Raiden rather than dying after falling off the roof of Federal Hall, though he is brain-dead. His clinical death occurs when he is removed from life support.


 * Sunny is revealed to be female despite Solid Snake referring to her as a male in the English version of Metal Gear Solid 2. In the Japanese version of Metal Gear Solid 2, however, there was no mention of the child's gender.


 * Liquid Ocelot is revealed to have been the person who helped Naomi escape from prison. It was previously implied by Nastasha Romanenko in her novel that Solid Snake was the person responsible for Naomi's escape. Solid Snake briefly alludes to this prior account in-game in Act 2, where he mentioned that his rap sheet was modified to include his "role" in her escape as a result.


 * Rosemary remarks that Roy Campbell had actually been Raiden's commanding officer, even though Campbell was revealed to have still been in retirement in Metal Gear Solid 2. The "Roy Campbell" who appeared in MGS2 was actually the Patriot AI GW aboard Arsenal Gear. It should be noted that it is not particularly clear if this is a retcon or just a continuity error.


 * Solid Snake's advanced aging is revealed to have been written into his genes in order to provide a fail-safe against Big Boss' clones falling into enemy hands, or if the clones turned against the Patriots under their own volition. It was previously claimed by Liquid Ocelot that the advanced aging was the result of the clones being created when Big Boss was in his late fifties.


 * Liquid Ocelot's possession by the spirit of Liquid Snake is revealed to be a result of nanomachines and hypnotherapy, rather than supernatural means.


 * Though not in the game itself, the supplemental Metal Gear Solid 4 Database inferred that Ocelot's affiliation with the OMON, the Russian Tax Police's elite SWAT team and the SVR, mentioned by Naomi Hunter in Metal Gear Solid during the boss battle against him, had in fact been falsified to cover up his Patriot-related activities.


 * The Metal Gear Solid 4 Database also states that the explosion seen by Solid Snake at the end of Metal Gear was not caused by the Outer Heaven self-destruct sequence initiated by Big Boss, but by the NATO bombing run previously described by Kyle Schninder in Metal Gear 2.
 * A large number of changes are made to the layout and contents of the Shadow Moses Island facility, see the article's "Behind the Scenes" section for more details. Most obviously there is an entire steel mill added below the furnace area, accessed via an elevator which did not exist before.
 * Snake is revealed to have always known the CQC techniques used by Big Boss in MGS3, but has consciously chosen not to use them until now. In reality, this was an excuse for retaining the CQC system rather than returning to the previous games' simplistic punch-punch-kick melee system.

Metal Gear Solid: Peace Walker

 * McDonell Miller's birth name is revealed to be Kazuhira, born in Japan to a Japanese mother and American father. In his previous backstory, as described in the Metal Gear 2 manual, he was a third generation Japanese-American.


 * Miller was aware of the Les Enfants Terribles project, more specifically the existence of two "sons" of Big Boss. It was previously stated in Metal Gear Solid that the only ones aware that Big Boss was Solid Snake's father during the Zanzibar Land Disturbance were Snake himself and Roy Campbell.


 * The Secret Call tape reveals that the idea behind the Patriots' AI system was first conceived in the 1970s.


 * Big Boss is revealed to have been 37 years old when the Les Enfants Terribles project took place, making him two decades younger than previously mentioned by Liquid Ocelot in Metal Gear Solid 2.


 * The Boss's participation in the Bay of Pigs Invasion was disinformation, as she had actually been in a coma during that time from an accident relating to the Mercury Project.


 * The MSX2 user's manual of Metal Gear described Big Boss as being a former member of the Green Berets, SAS, and GSG 9. Subsequent games retconned this, probably on the basis it would be practically impossible for an American citizen to serve in the latter two and had Big Boss only serve in the Green Berets and FOX before becoming a mercenary.


 * While Portable Ops already introduced a Metal Gear before TX-55 Metal Gear, Peace Walker introduces the first examples that fit the criteria of a "nuclear equipped walking battle tank" in Peace Walker and Metal Gear ZEKE, categorically contradicting the claim that TX-55 was the first such vehicle.


 * Fully functional REX-sized rail guns are seen on Chrysalis and Metal Gear ZEKE, with the latter capable of launching nuclear weapons, further altering the rail gun development dates from Metal Gear 2 and Metal Gear Solid.


 * The ending timeline states that Hal Emmerich was born in 1980. He was previously described as being in his thirties in 2005, according to his official biography for Metal Gear Solid.


 * Hal's only mention of his father's connection to the Emmerich family's "curse" of involvement with nuclear weapons in Metal Gear Solid was that he was born on the day Hiroshima was bombed. Peace Walker gives Huey a somewhat more storied history, including an incident where a robot he built almost blew up the world.

Metal Gear Solid: Social Ops

 * This game was the first to retcon the series' use of real-life weapons and equipment to the fictional designs that would later be used in the two V games.

Metal Gear Solid V: Ground Zeroes

 * The layout of Mother Base during the attack scene does not match the layout shown in Peace Walker.
 * The first canon entry in the series to retcon the use of real-life firearms and military equipment to fictional hybrid designs: going by the alterations in Social Ops, these fictional weapons are also supposed to have been used in every other entry in the series.

Metal Gear Solid V: The Phantom Pain

 * Everything involving the various parasites existing in the MGS universe even though they will never be so much as mentioned after this.
 * It is revealed that Otacon actually piloted a Metal Gear as a child at the behest of his father, and presumably lived in a robotics lab in Afghanistan for at least the first three or four years of his life rather than growing up in America as was previously assumed.


 * In Metal Gear 2, Gray Fox reveals to Solid Snake that Big Boss had rescued him from a forced labor camp after the Vietnam War. However, this is rendered impossible due to Big Boss being in a coma over a month before the end of the war and not waking up until sometime in early 1984.


 * Yevgeny Borisovitch Volgin is revealed to have survived Operation Snake Eater and fell into a coma. Earlier sources such as Portable Ops and the Metal Gear Solid 4 Database claimed he had actually been killed, with Metal Gear Solid 3 strongly implying such was the case. He eventually dies for good in Afghanistan after confronting Venom Snake.


 * Kazuhira Miller loses his right arm and left leg while in Afghanistan. He was previously depicted with a full set of limbs in official artwork produced for Metal Gear Solid.


 * Cipher is revealed to be the original name of the Patriots. Instead, the latter name was given to the AI network overseen by Donald Anderson.


 * It is now Venom Snake rather than Big Boss who is killed in Outer Heaven by Solid Snake, in the original Metal Gear. It was previously always clear that the Big Bosses in the first two Metal Gear games were the same person, and the first game's Big Boss was never depicted as missing his left arm or having shrapnel lodged in his head in any official artwork.


 * Ocelot mentioned that Zero founded the Patriots with Volgin's half of the Legacy. In Portable Ops, Ocelot already had the KGB's half of the Legacy when he killed the DCI to take the other half.


 * The war between Big Boss and Zero is given a different context. Specifically, Zero was in a persistent vegetative state by 1984 following a parasite infection, and he initiated development of an AI system as early as 1977 in order to implement his will. A large part of the conflict between Big Boss and Cipher was because of Skull Face's actions, not Zero's. In Metal Gear Solid 4, it was implied that the Patriots' AIs started development following Big Boss's coups d'état in the 1990s, and that Zero's mental state had deteriorated simply due to sickness and old age. In addition, Big Boss told Old Snake that Zero planted the second strain of the FOXDIE virus in him in order to kill the anti-Patriot faction.


 * Liquid is revealed to have been taken to the UK in 1976 after the abandonment of the "Les Enfants Terribles" project. In the Briefing File for Metal Gear Solid, it was indicated that Liquid had been taken to the UK upon his birth.
 * The Mammal Pod is revealed to have not been destroyed by either Big Boss ripping out its memory boards or the Boss AI's self-sacrificing destruction of Peace Walker, and instead was trawled up and sent to the Huey and Strangelove's robotics lab in Afghanistan, where it was bought back online for use in the creation of Sahelanthropus.
 * Liquid Snake is revealed to have met Psycho Mantis long before joining FOXHOUND and to have formed a strong bond with him, something never really implied by their interactions in Metal Gear Solid.