I've seen this brought up here and there, especially from people trying do deflect from the sheer ridiculousness of the Kingdom Hearts series, the idea that the Metal Gear Solid series are needlessly complicated that requires you to play every game in the series. Now, I've played every Metal Gear/Metal Gear Solid game (except the Acid series) and just don't understand how someone can get to this conclusion. The only game in the series that is needlessly convoluted is Metal Gear Solid 4, which we'll get into why that is shortly. But, let's break it down:
Metal Gear 1 & Metal Gear 2 (MSX): Old ass games from the bit era, they start Solid Snake and is your first introduction into the character as well as Big Boss, Gray Fox, FOXHOUND, Master Miller, and Metal Gear itself. However, the story is rather short, could be learned from a wiki, and is entirely skippable because of the next game in the series.
Metal Gear Solid (PS1): The first in the Solid series, signifying the series jump to 3D. And, is the introduction to the series for the majority of players. Due to this fact, the game spends plenty of time catching you up on the story from the past two MSX games, it assumes people are unfamiliar with them and weaves Snake's backstory into the narrative. The game is also basically a remake of Metal Gear 2 with characters swapped out. You don't need to play any prior game to understand its story or characters, it's all right there in the game. It's also a straightforward military/espionage story. Nothing truly complicated. The only game with as "clean" a narrative is MGS3.
Metal Gear Solid 2 (PS2): The sequel to MGS1, but while playing the previous game will greatly enhance the story, it's not a necessity. The game starts with Solid Snake, immediately catches the player up with who he is and what he's done since MGS1, and then proceeds to shuffle him to the side so the player can play a brand new character for the majority of the game. MGS2's star is Raiden and his story requires no knowledge of MGS1. Now, the meta-narrative is enriched by playing MGS1 as you come to understand what's going on. But, it's not required. Everything you need to know about MGS2 is explained in the game. The story itself is quite complicated, but it doesn't require outside knowledge. This is the game where MGS began to earn the meme of being "convoluted."
Metal Gear Solid 3 (PS2): Is a prequel to all other games and stars a new character, "Big Boss/Naked Snake." Absolutely no knowledge is needed of any prior game as it takes place before all of them. It's also a fairly direct story without a whole lot of weird twists or turns. It's about as "complicated" as a Bond film.
Metal Gear Solid 4 (PS3): The actually convoluted game. The wrap up to Solid Snake's journey that feels the need to reference every other game, including the MSX titles, tie all of them together, while at the same time being a sequel to game whose very narrative precludes the idea of a sequel being possible. One of the main reasons MGS4 is so convoluted is because MGS2 is a game that questions reality itself, it questions whether anything that happened in the game is real and has intentional inconsistencies in its narrative. How did Peter Stillman help you when Fatman said he died months ago? How did Snake escape the Tanker? How does Raiden not recognize the former President of the United States? MGS4 "solves" this by making everything that happened in MGS2 reality, even the inconsistencies. The result is a complicated narrative that is hard to make sense of even if you played all the games.
Metal Gear Solid: Portable Ops (PSP): Again, a prequel to every game except MGS3. While prior knowledge of MGS3 is helpful, it's not required. The game is very much an isolated incident and catches you immediately up to speed on the core details. Simple and Clean narrative. Again, a straight-forward military/espionage story.
Metal Gear Solid: Peace Walker (PS Vita): Another prequel starring Big Boss, also very Simple and Clean. Again, knowledge of MGS3 is helpful, but not required. The game goes to great lengths to explain to the player BB's backstory regarding MGS3. And, it pretends that Portable Ops doesn't exist. An easily understood narrative that is, once again, pretty straightforward.
Metal Gear Solid V (PS4/Xbone/PC): Is an actually complicated story, but not because it mandates knowledge from past games, but simply because the narrative is unfinished and what's there is poorly told. It don't matter if you've played every game, the story still doesn't make a whole lot of sense or conclude in a satisfying manner. Not a straight-forward narrative, a mess in every regard.
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So, from that list only two games could be said to require prior game knowledge, MGS4 and MGSV. They are also the games with the worst narratives. And, of all the games listed, the individual narratives themselves are all relatively straight-forward, save MGS4 and MGSV. They aren't impossibly dense or hard to follow, they are mostly straight forward military-espionage thrillers. Thus, has MGS as a series earned its perceived reputation of being a truly convoluted series?
Metal Gear 1 & Metal Gear 2 (MSX): Old ass games from the bit era, they start Solid Snake and is your first introduction into the character as well as Big Boss, Gray Fox, FOXHOUND, Master Miller, and Metal Gear itself. However, the story is rather short, could be learned from a wiki, and is entirely skippable because of the next game in the series.
Metal Gear Solid (PS1): The first in the Solid series, signifying the series jump to 3D. And, is the introduction to the series for the majority of players. Due to this fact, the game spends plenty of time catching you up on the story from the past two MSX games, it assumes people are unfamiliar with them and weaves Snake's backstory into the narrative. The game is also basically a remake of Metal Gear 2 with characters swapped out. You don't need to play any prior game to understand its story or characters, it's all right there in the game. It's also a straightforward military/espionage story. Nothing truly complicated. The only game with as "clean" a narrative is MGS3.
Metal Gear Solid 2 (PS2): The sequel to MGS1, but while playing the previous game will greatly enhance the story, it's not a necessity. The game starts with Solid Snake, immediately catches the player up with who he is and what he's done since MGS1, and then proceeds to shuffle him to the side so the player can play a brand new character for the majority of the game. MGS2's star is Raiden and his story requires no knowledge of MGS1. Now, the meta-narrative is enriched by playing MGS1 as you come to understand what's going on. But, it's not required. Everything you need to know about MGS2 is explained in the game. The story itself is quite complicated, but it doesn't require outside knowledge. This is the game where MGS began to earn the meme of being "convoluted."
Metal Gear Solid 3 (PS2): Is a prequel to all other games and stars a new character, "Big Boss/Naked Snake." Absolutely no knowledge is needed of any prior game as it takes place before all of them. It's also a fairly direct story without a whole lot of weird twists or turns. It's about as "complicated" as a Bond film.
Metal Gear Solid 4 (PS3): The actually convoluted game. The wrap up to Solid Snake's journey that feels the need to reference every other game, including the MSX titles, tie all of them together, while at the same time being a sequel to game whose very narrative precludes the idea of a sequel being possible. One of the main reasons MGS4 is so convoluted is because MGS2 is a game that questions reality itself, it questions whether anything that happened in the game is real and has intentional inconsistencies in its narrative. How did Peter Stillman help you when Fatman said he died months ago? How did Snake escape the Tanker? How does Raiden not recognize the former President of the United States? MGS4 "solves" this by making everything that happened in MGS2 reality, even the inconsistencies. The result is a complicated narrative that is hard to make sense of even if you played all the games.
Metal Gear Solid: Portable Ops (PSP): Again, a prequel to every game except MGS3. While prior knowledge of MGS3 is helpful, it's not required. The game is very much an isolated incident and catches you immediately up to speed on the core details. Simple and Clean narrative. Again, a straight-forward military/espionage story.
Metal Gear Solid: Peace Walker (PS Vita): Another prequel starring Big Boss, also very Simple and Clean. Again, knowledge of MGS3 is helpful, but not required. The game goes to great lengths to explain to the player BB's backstory regarding MGS3. And, it pretends that Portable Ops doesn't exist. An easily understood narrative that is, once again, pretty straightforward.
Metal Gear Solid V (PS4/Xbone/PC): Is an actually complicated story, but not because it mandates knowledge from past games, but simply because the narrative is unfinished and what's there is poorly told. It don't matter if you've played every game, the story still doesn't make a whole lot of sense or conclude in a satisfying manner. Not a straight-forward narrative, a mess in every regard.
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So, from that list only two games could be said to require prior game knowledge, MGS4 and MGSV. They are also the games with the worst narratives. And, of all the games listed, the individual narratives themselves are all relatively straight-forward, save MGS4 and MGSV. They aren't impossibly dense or hard to follow, they are mostly straight forward military-espionage thrillers. Thus, has MGS as a series earned its perceived reputation of being a truly convoluted series?