Similarities between games

The following is a list of similarities between games in the Metal Gear series. The games often have recurring themes, visual motifs and plot devices.

Codec

 * Codec Frequencies. Although slightly obvious, Codec frequencies in each game are sometimes shared among similar characters.
 * 140.85 is used for the lead character's commanding officer (or, in the case of Metal Gear Solid: Portable Ops, his second-in-command). The frequency contacts Big Boss in Metal Gear (where it is 120.85); Roy Campbell in Metal Gear Solid: Portable Ops, Metal Gear 2: Solid Snake, Metal Gear Solid/Metal Gear Solid: The Twin Snakes, Metal Gear Solid 4: Guns of the Patriots, and Super Smash Bros. Brawl; GW impersonating Campbell in Metal Gear Solid 2: Sons of Liberty; Major Zero in Metal Gear Solid 3: Snake Eater. In Metal Gear and Metal Gear Solid 2, this character eventually betrays the main character and feeds him false information or gives him self-destructive instructions. In Super Smash Bros. Brawl, Slippy Toad hijacks Campbell's frequency if the player uses the Codec while fighting Falco.
 * 140.96 is used to record mission data (i.e. save the game). In Metal Gear Solid, the Tanker section of Metal Gear Solid 2, and Metal Gear Solid 3, after saving the game, the character who the player contacts via the frequency makes small talk about a certain field of interest. In Metal Gear Solid 3, Portable Ops, and the Tanker section of Metal Gear Solid 2, the save game frequency is the secondary Codec frequency of the character who saves the player's game. Mei Ling also uses this frequency to talk to Snake in Super Smash Bros. Brawl.
 * 141.80 is used for someone whom the lead character looks up to as a mentor or idolizes (or vice versa) who often ends up having a secret identity. In Metal Gear 2: Solid Snake, 140.38 is used by Master Miller; in Metal Gear Solid, Master Miller turns out to be Liquid Snake; in Metal Gear Solid 2: Sons of Liberty, Iriquois Pliskin is Solid Snake in disguise; in Metal Gear Solid 3: Snake Eater, The Boss defects to the Soviet Union; and in Metal Gear Solid 4: Guns of the Patriots, Raiden has become a Cyborg Ninja.
 * 140.48 is used by anonymous callers in Metal Gear 2: Solid Snake, Metal Gear Solid and Metal Gear Solid 2; they use pseudonyms on the Codec ("#1 Fan", "Deepthroat", and "Mr. X", respectively). They assist the main character via Codec, even though they work against the main character at times.
 * 140.15 is used to contact a female comrade in Metal Gear 2, Metal Gear Solid, and Metal Gear Solid 4.
 * 141.12 is used by Otacon in Metal Gear Solid, Metal Gear Solid 2, Metal Gear Solid 4, and Super Smash Bros. Brawl.
 * 141.52 is used by a female technical adviser in Metal Gear Solid and Metal Gear Solid 2.
 * 142.52 is used to contact EVA in both Metal Gear Solid 3 and Portable Ops.

Main Character

 * The lead character being captured, and in some cases, tortured.
 * In Metal Gear, Solid Snake needs to be captured in order to locate Gray Fox.
 * In Metal Gear 2, Solid Snake is briefly captured alongside Holly White near the end of the game, but they are rescued by Charlie soon after.
 * In Metal Gear Solid, Snake is captured by Sniper Wolf and then tortured by Ocelot, who threatens to kill Meryl, who Snake had grown close to.
 * In Metal Gear Solid 2, Raiden is captured by Olga. He's then "tortured" by Solidus Snake in a direct recreation of the torture room from Metal Gear Solid. The capture turns out to be a way for Snake to infiltrate Arsenal Gear.
 * In Metal Gear Solid 3, Naked Snake is captured and tortured by Volgin.
 * In Metal Gear Solid 4, Old Snake is forced to go through a microwave hallway, "torturing" Snake by cooking him alive and occasionally shocking him, and in order to proceed through the hallway, the player must rapidly tap the Action button in a manner nearly identical to the torture scene from MSG1, except that you cannot "submit" to the torture. Note that while Old Snake isn't actually caught nor imprisoned by the game's main antagonist, in a sense, Old Snake was "caught" and "tortured" by GW.
 * In Metal Gear Solid: Portable Ops, Naked Snake begins the game in a cell and is tortured by Cunningham. He is later captured again.


 * The main character starts off with one mission, however his purpose is actually something different.
 * MG1 - Big Boss had the rookie Snake sent to Outer Heaven, hoping to have him captured and feed misinformation to authorities, underestimating Snake's ability.
 * MG2 - Snake is intially sent to rescue Dr. Marv, but the mission later on is to recover the Oilix formula and destroy Metal Gear D.
 * MGS1 – Snake is sent to infect FOXHOUND with FOXDIE.
 * MGS2 – Raiden is the test subject for the S3 Plan.
 * MGS3 – Naked Snake helps America steal the Philosophers Legacy.
 * MGS4 – Snake is used to to infect the remaining founding members of The Patriots (except for Zero) with FOXDIE. Snake also destroys The Patriots' AI and brings back Big Boss, a purpose that had been planned for him since his infiltration at Shadow Moses.


 * Eye patches. In Metal Gear Solid 3, Portable Ops, Metal Gear 2, and artwork for Metal Gear Solid and Metal Gear Solid 4, Big Boss is seen wearing an eye patch (although he also appears in Metal Gear, his eye patch is not clearly visible). In Metal Gear Solid 2, Solidus Snake damages his eye and wears an eye patch, but on a different eye. In Metal Gear Solid 4, Solid Snake is seen using the Solid Eye system which he wears like an eye patch over the same eye Solidus wore his.


 * Snake landing in a pose near the beginning of the game while disguised in some way, at which point he raises his head and fully reveals himself to the player. This occurs in the cutscene after you get to the elevator at the beginning of Metal Gear Solid and The Twin Snakes, at the start of MGS2's Tanker chapter after his Stealth Camouflage fails, at the start of MGS3 after parachuting into the USSR, and in MGS4 after losing his militia outfit.
 * Drebin and his pet monkey Little Grey parody this landing pose at one point in MGS4, shattering the drama by belching loudly after posing.

Cyborg Ninja

 * The return of a major character from a former game disguised as a ninja. The character's true identity is initially concealed. First used in Metal Gear 2 with Kyle Schneider, then Metal Gear Solid with Gray Fox and finally in Metal Gear Solid 4 with Raiden. After appearing as herself in the Tanker chapter of Metal Gear Solid 2, Olga reappears as a ninja in the Big Shell chapter.


 * A Cyborg Ninja telling the main character to hurry after saving them. Gray Fox says "Hurry, get away!" after saving Snake from REX, Olga says the same thing after saving Raiden. In Metal Gear Solid 4, Raiden says "Hurry!" to Snake after stopping Outer Haven from crushing him.

Other Characters

 * A scientist that the main character must rescue: Dr. Drago Pettrovich Madnar (MG and MG2), Dr. Kio Marv (MG2), Otacon (MGS1), Emma (MGS2), Sokolov (MGS3), and Naomi Hunter (MGS4).


 * A scientist that at some point loses bladder control out of fear: Otacon (MGS1), Emma (MGS2), and Sokolov (MGS3).


 * Johnny and his bowel problems. MGS1, MGS2, MGS3, MGS4. MGS3's Johnny is the grandfather of the Johnny from the rest of the series.


 * Some one Otacon cares for/loves dies. Sniper Wolf in MGS1, Emma in MGS2, and Naomi in MGS4.

Quotes

 * The use of the line "It's not over yet." Originally said by Big Boss in Metal Gear 2, later to be said again by Liquid Snake in Metal Gear Solid, Olga in Metal Gear Solid 2, Volgin in Metal Gear Solid 3, and Sokolov in Metal Gear Solid: Portable Ops. Liquid Ocelot in Metal Gear Solid 4, as well as a variation in Act 4 in Shadow Moses "It's not over! Not yet!" when he arrives in Metal Gear RAY. Liquid also uses this line Metal Gear Online if he is on the losing team and is killed just before the end of the match, right before rising again and extending the match for another forty seconds.


 * In Metal Gear Solid 2: Sons of Liberty and Metal Gear Solid 3: Snake Eater, there is a line of dialog at the beginning of each game where Snake says "Kept you waiting, huh?" This very sneakily breaks the Fourth wall. The line is not used in-game in Metal Gear Solid 4, but Snake does say after the initial 8-minute installation when the game is loaded for the very first time. Also, in Super Smash Bros. Brawl, Solid Snake says the line at the beginning of every match, and in a trailer. During the Subspace Emissary there is a cut scene fairly early on of Snake's Box. Much later in the game Snake is seen emerging from the box, where he then turns to the camera and says "Kept you waiting, huh?" It is also said in the Snake Tales story External Gazer by an alternate universe version of Solidus Snake, when he say to Mei Ling "Kept you waiting, huh?"


 * The use of the line "neither enemy, nor friend." Used by Gray Fox in Metal Gear Solid, Olga while in the cyborg ninja suit as Mr. X in Metal Gear Solid 2, and by Drebin in Metal Gear Solid 4.


 * In Metal Gear Solid/The Twin Snakes and Metal Gear Solid 3, both Snakes get tortured and ask a support member to tell them a story to take their minds off the pain they feel at the time.


 * In Metal Gear Solid, Ocelot tells Solid Snake "You're pretty good" after being defeated. In Metal Gear Solid 3, Naked Snake says when he first defeats Ocelot. Liquid Ocelot also says this when he's beaten by Old Snake in MGS4.
 * In Metal Gear Solid 2: Sons of Liberty and Metal Gear Solid 3:  Snake Eater, someone says the line:  "There's room for only one Snake and one (Big) Boss."  Said by Liquid Snake uppon his departure in MGS2, and by The Boss uppon her death in MGS3.

Games

 * Battles with an aircraft. In Metal Gear, Metal Gear 2 and Metal Gear Solid they were Hind D choppers. In Metal Gear Solid 2 it was a Harrier II jump jet. In both these situations Snake uses attacks the aircraft with stinger missiles. Naked Snake can evade or destroy Hind A choppers in Metal Gear Solid 3, but these are not mandatory boss battles as they were in previous games.


 * After the end credits there will be a sequence where a huge plot twist is revealed. In Metal Gear Solid, Metal Gear Solid 3, and Metal Gear Solid: Portable Ops, the character doing all of the talking is Ocelot. While in Metal Gear Solid 2 and Metal Gear Solid 4, the talk is between Solid Snake and Otacon.


 * Sea insertion is the primary method of infiltration into the enemy stronghold in Metal Gear, Metal Gear 2, Metal Gear Solid, and the Plant Chapter of Metal Gear Solid 2.


 * A one-on-one fight without any firearms between the protagonist and one of the final bosses, in MG2, MGS and MGS2.


 * A final Boss battle where there is a time limit caused by a bombing raid. In MGS, B-2 bombers are sent to destroy Shadow Moses while Solid Snake fights Liquid. In MGS3, MIGs are sent to bomb the field where Naked Snake and The Boss fight. Although not a boss battle, in MGS4, Snake has to escape on Metal Gear REX with 5 minutes before the Gekko explode.


 * In the final boss battle there is the added tension that another character may have died or may die as a consequence of the battle. MGS, Meryl appears to have died during torture. MGS2, Sunny will be killed by The Patriots if Raiden fails.MGS3, killing The Boss is Snakes mission even though he doesn't want to kill her.


 * Often the antagonist is trying to create Outer Heaven, a nation of soldiers, in MG, MG2, MGS and MGS4.

Plot elements

 * The game opening with a cliff-side open environment before moving inside to a tank-storage room with an elevator.
 * Master Miller giving advice on improving one's health and professional life.
 * Saving a hostage who appears on radar. In addition, the first hostage of the game is a disguised member of the terrorist faction.
 * Meeting a disguised female contact in a women's washroom.
 * Snake and his female contact effectively becoming romantiacally involved. Holly in Metal Gear 2 and Meryl in Metal Gear Solid/The Twin Snakes.
 * Helpful messages from an anonymous source via the radio claiming to be a fan of Snake, who turns out to be Gray Fox in both cases.
 * An ally from the previous game betrays Snake (Dr. Madnar in Metal Gear 2 and Master Miller in Metal Gear Solid).
 * A disguised female contact sneaks up on Snake (Holly in Metal Gear 2 and Meryl in Metal Gear Solid/The Twin Snakes).

Boss battles

 * The return of a major character from the former game decked out as a ninja (Kyle Schneider in MG2 and Gray Fox in MGS).
 * An ambush by four hidden attackers in an elevator.
 * A fight with a soldier wearing stealth camouflage.
 * An unarmed hand-to-hand showdown (between Snake and Gray Fox in MG2, and between Solid Snake and Liquid Snake in MGS).
 * After destroying the Metal Gear of the game, then having a hand-to-hand fight with the pilot.

Misc

 * A chase up a spiral staircase with soldiers in pursuit.
 * Having to look at the back of the game package to learn an important radio frequency.
 * Having to change the temperature of an object to turn it into a key.
 * Having to heat up frozen rations before eating them.

Similarities Between Metal Gear Solid and Metal Gear Solid 2: Sons of Liberty
Many, if not all, of the following similarities between the two games are the intentional results of the S3 Plan, The aim of the plan according to Revolver Ocelot was to turn a rookie such as Raiden into a recreation of Solid Snake. However, it is later revealed by GW that this is not the true aim.

Boss Battles

 * The first boss is a short-range gunfight with obstacles blocking the player's line of sight and preventing him from getting close to his opponent: Revolver Ocelot in Metal Gear Solid, Olga in Metal Gear Solid 2. Explosives are the worst enemies to Snake in both of these battles. If Snake steps over the square line around Kenneth Baker or uses an explosive weapon to combat Ocelot, the entire room will be filled with explosions. Olga can toss grenades at Snake, which can cause him serious damage or death.


 * Additionally, each enemy leader pilots an aerial assault on the main character during a transition between two areas: Liquid attacks Snake with a Hind D on the communications tower, and Solidus attacks Raiden with a Harrier II on the Shell 1-2 connecting bridge. Although both aircraft are destroyed with Stinger missiles, the area where the battle occurred is destroyed in the fight, and the pilot is quickly revealed to have survived.


 * Both Vulcan Raven and Fatman play a game of cat-and-mouse with the main character while firing automatic weapons at him. The field of each battle is cluttered with metal storage units that the enemy occasionally targets with his main weapon: Raven destroys crates to impede Snake's movement, while Fatman plants bombs that will destroy the entire heliport if not disarmed.


 * Raiden's battle with Vamp is similar to Snake's battle with the Ninja: both bosses run and leap with great speed, both are capable of escaping from sight for a time, both are immune to gunfire under certain circumstances, and both close in for melee combat once they are sufficiently wounded.


 * Metal Gear REX and Metal Gear RAY are both especially vulnerable in their open mouths, and both can only be destroyed by Stinger missiles.


 * The final battle in each game is fought in close quarters in an open, flat, high-elevation area. Liquid and Solid Snake battle bare-fisted atop the wreck of Metal Gear REX. Solidus and Raiden battle with swords in the shadow of the wreck of Arsenal Gear. Both Liquid and Solidus will charge at their opponents, potentially causing heavy damage or knocking the main character off the battlefield to his death if he leaves himself open.

Cyborg Ninja

 * The scene where Raiden sees the soldiers killed by Vamp is similar to the one where Snake sees the Cyborg Ninja for the first time. The similarity is underscored during the initial revelation of the S3 Plan, which transposes flashbacks to the two scenes.


 * The appearance of a Cyborg Ninja in a role that alternately assists and antagonizes the main character. Both Cyborg Ninjas are bosses in the games in which they appear, although Olga is a boss before she becomes the Ninja.


 * An identical exchange of dialog occurs between Snake and a mysterious stranger, telling him there are claymore mines in a location, he should use a mine detector, call the person "Deepthroat," and that the mysterious caller is "one of (his) fans."

Names

 * The beginning of both games involves a vessel called the Discovery.


 * The code name of the operative being "Snake", although Jack's is changed to Raiden very early into his first mission.


 * The terrorist groups in both games have similar names, Sons of Big Boss and Sons of Liberty.


 * A "president" is kidnapped in both situations. In Metal Gear Solid it was Kenneth Baker, President of ArmsTech. In Metal Gear Solid 2 it was the President of the United States, James Johnson.


 * A "president" dies shortly after meeting the main character and Revolver Ocelot. In MGS1 Kenneth Baker dies after coming into contact with Snake from the effects of FOXDIE. In MGS2 James Johnson is shot by Ocelot after Raiden refuses to kill him.


 * Vulcan Raven and Vamp respectively refer to Ocelot as "General Ivan" and "Crazy Ivan", a racial ephitet for persons of Russian ethnicity.


 * Revolver Ocelot calls Snake a "carrier boy" in the torture room, his secret way of talking about the FOXDIE that Naomi injected into Snake. He also calls Raiden that after he shoots President Johnson, referring to the disk that contains the virus to destroy GW that Raiden is holding.


 * The leader of the terrorist group in each game is a clone of Big Boss: Liquid Snake in Metal Gear Solid, Solidus Snake in Metal Gear Solid 2. In both games, the character's use of the codename "Snake" is played up in contrast to Solid Snake early in the mission.

Misc

 * Both FOXHOUND and Dead Cell are rogue special-ops government outfits.


 * Both of games take place in a far off, remote American facility that is secretly housing a new Metal Gear, Metal Gear REX in Metal Gear Solid, Arsenal Gear in Metal Gear Solid 2.


 * Revolver Ocelot is a member of both terrorist groups, and is effectively the second-in-command of each group.


 * Someone that helps the lead character dies of an apparent heart attack that was actually caused by nanomachines: Donald Anderson in Metal Gear Solid (he was actually Decoy Octopus, and was killed by FOXDIE), and Richard Ames in Metal Gear Solid 2 (he was actually an agent of of The Patriots who killed him by remotely shutting down his pacemaker).


 * Otacon and Emma Emmerich fulfill similar roles in each game. In addition to the obvious fact that they are stepsiblings, both are gifted scientists who worked on the latest Metal Gear in order to overcome issues with their family: Otacon to atone for his grandfather's actions, Emma to gain revenge against Otacon and to force him to see her as a woman. Both also wet their pants upon being revealed for the first time in both games.


 * In addition to the previous, both Otacon and Emma Emmerich hide in lockers and fear their rescuer.


 * The player is given the option to save a female associate from death at the hands of the terrorists. Snake can choose to give in to Ocelot's torture and let Meryl die, although canonically, he endures the torture and she lives. Raiden saves Emma from being instantly killed by Vamp, although the wounds that Vamp inflicts on her ultimately prove to be fatal.


 * The torture room in Metal Gear Solid 2 is an exact recreation of the same room in Metal Gear Solid. The cell that Snake escaped from in Metal Gear Solid is visible through the window in the torture room in Metal Gear Solid 2. In both games, the player may be freed by the Cyborg Ninja, although Snake can escape from his cell in Metal Gear Solid before being rescued by the Ninja.

Metal Gear Solid: Portable Ops
Portable Ops contains some references to other games in the series.
 * The relationship between Big Boss and Gene is similar to the one between Solid Snake and Liquid Snake. Gene is the end result of the Successor Project, a project designed to infuse a soldier with The Boss' genes (also a precursor to the Les Enfants Terribles project). Gene even goes so far as to call Big Boss "brother."
 * In Metal Gear Solid, Solid Snake has to take down his former unit, FOXHOUND. In Portable Ops, Naked Snake has to take down his former unit, FOX.
 * In Metal Gear Solid 3 there is a backwards interrogation where Volgin reveals information about the legacy that Snake did not know. in Portable Ops Cunningham reveals that he is working for the pentagon While threatening Snake and his men.
 * The music in general is similar to music from Metal Gear Solid 3, and two specific songs are remakes of songs from Metal Gear Solid 2. The track "Sad Man's Theme" is a remake of "Peter's Theme" and "Evasion" is a remake of "Countdown to Disaster."
 * Big Boss' last action in this game is to salute his comrades. This is similar to his last action in Metal Gear Solid 3 and Metal Gear Solid 4, where he salutes The Boss' grave.