[RedDragon]

Also, for all the strange powers the characters seem to possess:

Nanomachines, son!: These are the ultimate Deus Ex Machina in MGS (I swear, they must appear at least 300 times in the script of MGR": Reveangence). Nanomachines in the Metal Gear series grant abilities that are far beyond those they could ever reasonably bestow in real life. Also, considering the powers they give (e.g. Instantly healing from near-fatal wounds, or running up 90-degree walls [Yeah, I'm talking about you, Vamp!]), they seem to be remarkably inexpensive. Whenever a character displays abilities that should be impossible for a human being to perform, or even blatantly violate all known laws of physics, they can be hand-waved away with the simple phrase, "Oh, looks like he has nanomachines." Nanomachines can be used to grant most physical and mental disadvantages in the GURPS System, 3rd edition or 4th edition. The cost of Nanomachine insertion operations is $200 x the point cost of the abilities granted (negative points are treated as positive points for the purpose of determining dollar cost).

Also, for those new to the series, the established timeline (of the main series games and important events outside of those games) is as follows:
(!Small Spoilers!)

1962: Soviet nuclear research scientist Sokolov defects to the U.S. The Cuban Missile Crisis.
1964: The events of Metal Gear Solid 3: Snake Eater: The Virtuous Mission and Operation Snake Eater.
1970: The events of Metal Gear Solid: Portable Ops: The San Hieronymo Incident.
1972: The Les Enfants Terribles Project.
1974: The events of Metal Gear Solid: Peace Walker: The Peace Walker Incident.
1975: The events of Metal Gear Solid V: Ground Zeroes: The XOF Trojan Horse Operation.
1984: The events of Metal Gear Solid V: The Phantom Pain (please note that MGS V has not been released yet, and all we have to go on are the trailers, gameplay and story segments shown off at conventions, and various other promotional material. The game's position in the timeline may change.)
1995: The events of Metal Gear: The Outer Heaven Uprising and Operation Intrude N313.
1999: The events of Metal Gear 2: Solid Snake: The Zanzibar Land Disturbance and Operation Intrude F014.
2003: The assassination of Dr. Clark by the newly cyborged Frank Jaeger, AKA Gray Fox.
2005: The Events of Metal Gear Solid: The Shadow Moses Incident.
2007 and 2009: The events of Metal Gear Solid 2: Sons of Liberty: The Tanker Incident in 2007, and the Big Shell Incident in 2009.
2008: The Liquidation of the Dead Cell, a smear campaign organized by the Patriots against the counter-terrorist SEAL team Dead Cell.
2014: The events of Metal Gear Solid 4: Guns of the Patriots: Liquid Sun, Solid Sun, Third Sun, Twin Suns, Old Sun, and Naked Sin.
2016: The events of the Metal Gear Rising: Revengeance "Jetstream" DLC: The Raid on World Marshall.
2018: The events of Metal Gear Rising: Revengeance: The Ambush at Africa, The Abkhazian Coup, The Investigation at Guadalajara, The Raid at Denver, and Operation Tecumseh.

There are also many Non-Canon, Re-releases, Deluxe Versions and Spin-Off Games, which I will list below, in as close to chronological order as I can get (they aren't as well fleshed out as the Main Series Games):

Metal Gear: Ghost Babel: Set in 2002, this is an alternate sequel to the original Metal Gear published for the Gameboy Color. It received high scores.

The Metal Gear Acid Series: Metal Gear Acid and Metal Gear Acid 2, plus Metal Gear Acid Portable and Metal Gear Acid Portable 3D (which were stripped-down versions of the original Metal Gear Acid), which was a turn-based tactical strategy game, featuring cards which represented soldiers.

Metal Gear: This is the American-release NES version of the original Metal Gear Game on the MSX. It was produced without Hideo Kojima's involvement and thus turned out differently than the original. Despite this, it achieved critical success in America and spawned it's own sequel (the also-non canon) Metal Gear 2: Snakes Revenge.

Metal Gear Arcade: A Japan-only arcade game based on Metal Gear Online (See below). It was removed shortly due to poor sales.

Metal Gear Online: An online multiplayer game based on the MGS 4 gameplay and setting. The servers closed for good in 2008, but a sequel is planned to be released around the same time as MGS V: The Phantom Pain.

Metal Gear Solid Mobile: A game released for mobile phones which takes place between MGS and MGS 2. There were some interesting ways to use the phone camera in-game, like using it to aim remote-controlled missiles.

Metal Gear Solid Touch: Another mobile game, this one a retelling of MGS 4. It received mixed reviews.

Metal Gear Solid: Social Ops: An online game with a story based on MGS 3 and MGS Peace Walker, similar to Metal Gear Acid in that it utilized cards and was a turn-based tactical game. It's servers have been shut down.

Metal Gear Solid: Piece Walker: A flash-based jigsaw game released to promote MGS: Peace Walker.

Ganbare Snake: A downloadable mobile game that was a crossover between MGS 4 and Ganbare Salary Man. The download is no longer available.

Re-releases and Deluxe Editions: Metal Gear Solid 2: Substance, Metal Gear Solid 3: Subsistence, Metal Gear Solid: Integral, Metal Gear Solid: Portable Ops Plus, Metal Gear Solid: Snake Eater 3D, Metal Gear Solid: The Essential Collection, Metal Gear Solid: The Legacy Collection, Metal Gear Solid: The Twin Snakes, Metal Gear Solid: HD Collection, and the Metal Gear 20th Anniversary: Metal Gear Solid Collection: These are all re-releases or Deluxe Versions. Mostly they feature enhanced graphics, extra game modes, and the like, although a few provide new story content.

In addition, there have been many MGS releases in other media, including a boardgame, soundtrack CDs, and a novel.