Metal Gear Solid V Hideo Kojima Interview Special - DidYouKnowGaming VGFacts
Metal Gear Solid Part 3 - Easter Egg Hunting
Hideo Kojima said that if Konami hadn't released Castlevania, and Capcom hadn't released Ghosts 'n Goblins, Metal Gear might not have been made. At the time, Kojima wanted to create a horror game. He felt that Castlevania and Ghosts 'n Goblins covered all the ground in action horror games that he wanted to cover, and that there was no point in making a new horror game.
Contributed by Verusgate
Despite the name, there is no Metal Gear weapon in the NES version. Due to the hardware limitations, the Metal Gear fought in the MSX version is replaced with a super computer that the player must blow up.
Contributed by gamemaster1991
The book cover for the novelization of the original Metal Gear removed the gun from Snake's hand. While Snake collects many weapons throughout the book, which describes him as a "walking arsenal", he never shoots anyone with them. Seth Godin, creator of the "Worlds of Power" book series, "wanted to minimize the death" seen in many of the NES games.
Contributed by Pogue-Mahone
The Japanese MSX2 manual of Metal Gear displays Big Boss's eyepatch on his left eye, although his character sprite displays it on his right.
Contributed by SOGESNAKE
The game was designed as a stealth game involving avoiding confrontation due to the limitations of the MSX2 at the time. If there were a large number of character sprites on screen at one time there would be a lot of sprite flickering and slowdown. The game was instead changed to involve the player using stealth to avoid enemy confrontations.

"The company asked me to create a combat game. Actually, a senior associate had been in charge of it but he was stuck and I was asked to do it. You could not have more than four bullets with MSX, and that meant you could only have two to three enemies. You cannot make a combat game with that. So I came up with a game like 'The Great Escape' where the prisoner had to escape. it was an idea born from adverse situations." - Hideo Kojima speaking to Retro Gamer Magazine (Issue 35, Page 74)
Contributed by MightyKombat
Kojima personally hated Metal Gear on the NES, and has gone on to say that he couldn't even get past the first scene of this port.
Contributed by Cavery210
NSFW - This trivia is considered "Not Safe for Work" - Click to Reveal
The North American and Japanese versions of the game have a password which takes the player to the final boss fight unarmed. It reads 'FUCKM E1111 11111 11111'

The European version of the game had it's character grid modified to prevent vulgar passwords being entered.
Contributed by IkiFoo
The cover to the game is a redrawn image of Terminator actor Michael Biehn (Kyle Reese).
Contributed by gamemaster1991