If Mei Ling is called multiple times and the player chooses "Do Not Save" each time, she'll begin to chastise Snake. On the third time, she'll say "C'mon Snake. Don't call me for no reason." On the fourth call, she'll say nothing at all. On the sixth call, she will not give the player a chance to save and will instead stick her tongue out.

Rotating the analog sticks and directional pad while on the title screen/menu will change the colors in the background.

When booting up the game, a short music track will play as the Konami logos appear during the title sequence. The music that plays is actually an extract from a theme called "End of the Dark" from the game Policenauts.

If the player forgets/can't find the SOCOM Pistol before meeting Meryl for the first time, the cutscene of their first encounter will be slightly different; Normally, Snake pulls out his pistol and aims it at Meryl, but being without a pistol makes him put his hand on the tip of Meryl's FAMAS.

The battle with Psycho Mantis includes a pre-fight "demonstration" of Mantis' psychic abilities, in which Mantis will read the player's memory card. If the player has save data from one of several Konami PlayStation games on their memory card, Mantis will reference that game by name. The games that trigger this dialogue are Suikoden, Castlevania: Symphony of the Night, Vandal Hearts and Azure Dreams.

In the Japanese release, both Policenauts and Snatcher are also recognized. Having save data from both of these games will trigger a message from Hideo Kojima, thanking the player for their continued support, but since both of those games were only released in Japan, this message cannot be heard normally in international versions of the game.

There are a number of cut animations first found within the "Pilot Disk" demo, and later found to also be in the final Japanese and American releases. One of them is a jumping roundhouse kick, which would later appear in Metal Gear Solid 2: Sons Of Liberty.

The word Solid in the title has three meanings. The first refers to the main character, Soild Snake. The second comes from the fact that this was the first 3D Metal Gear game. The last meaning is a take on the rival company, Square. As Hideo Kojima said, "A square is a two- dimension thing. And I guess the president of Konami wanted this game to surpass Square. They wanted to make it a cube, you know, like solid 3D."

The Metal Gear Solid: Official Mission Handbook, published in 1998 by Millennium Books, gave an alternate account of Big Boss's early years. This information has since been retconned in more recent games. The guidebook read:

Snake's real name, David, was not a reference to his voice actor, David Hayter, as it was present in the Japanese script long before he was hired to provide Snake's voice. The name is instead a dual reference to 2001: A Space Odyssey and Policenauts.

In Otacon's ending, Snake gives Otacon his real name, and Otacon replies "I'm Hal, Dave." to which Snake jokes they should "take a trip to Jupiter", referencing the Stanley Kubrick 1968 movie and book 2001: A Space Odyssey which starred a main character named "David" Bowman and the famous supercomputer "HAL"-9000.

In Meryl's ending, Snake gives his real name to Meryl, who calls him "Dave". This is actually one of many references to Kojima's previous game Policenauts, in which Meryl Silverburgh was a member of the Beyond Coast Polices Vice unit, and was partnered with a young officer named "Dave" Forrest.

Depending on the selected difficulty level, the number of times that Snake will have to endure torture by electric shock is different, and Revolver Ocelot will have a different comment each time.

• Easy: 3 - "Had enough yet? We're not finished yet!"
• Normal: 4 - "You're still okay? Want me to go on? Can you take one more?"
• Hard: 5 - "Give up. Make it easy on yourself. One more time!"
• Extreme: 6 - "Come on! You don't want to die like this, do you? I can do this all day!"

This was changed in the Twin Snakes version to be 3 rounds, regardless of the difficulty setting.

Inside Hal's lab, there is either a PlayStation with a DualShock controller (in the original PlayStation version of the game) or a Gamecube with a Wavebird controller and statuettes of Mario and Yoshi (in the Twin Snakes remake). Shooting Mario will give the player some health while playing the 1-up sound.

In the 2nd half of the battle, Metal Gear Rex can be defeated with the PSG1.

The production team came up with many designs for the game's areas by building miniatures out of LEGO.

Solid Snake's design in Metal Gear Solid was inspired by the body of Jean Claude Van-Damme and the face of Christopher Walken.

Meryl Silverburgh shares her name with a character from Kojima's earlier game Policenauts, and both Meryls were voiced by the same woman in Japan.

Christopher Randolph, the voice of Otacon, actually first auditioned for the role of Solid Snake. The producers didn't think that Randolph fit, but instead wanted him to try auditioning as Otacon, as Randolph looked almost identical to Otacon's concept art at the time.

When playing on a mono-sound TV, or the audio is set to mono in the settings, calling Colonel Campbell a few times during the Hind battle will cause Snake's team to playfully mock him about not having a stereo TV.

Bleem! was a PlayStation emulator released for Microsoft Windows 98 and the Sega Dreamcast. Unlike the vast majority of emulators before and since, it was released as a paid product on store shelves. Bleem!, although very impressive for the time and capable of running on low-end PCs, had many compatability issues, with the only game that ran perfectly on Windows Bleem! being the US version of One, while the only games that could be run at all on Dreamcast were Tekken 3, Metal Gear Solid, and Gran Turismo 2, all with specialised emulators released on their own "Bleemcast" discs.

Sony would sue Bleem! twice over alleged copyright infringement, and despite all odds, Sony lost due to Bleem!'s use of screenshots in promo material and the PS1 BIOS being protected by fair use. However, a mix of legal fees and Sony threatening retailers stocking Bleem! products with subpoenas would force Bleem! off of shelves anyway, and its website would be replaced with an image of Sonic the Hedgehog mourning at a grave with the Bleem! logo carved on it. Bleem! would countersue Sony for anti-competitive activity.

The popularity of Bleem! would lead both Sega and Microsoft to attempt to work with Bleem! officially to make PS1 games run on Dreamcast and Xbox, though these plans fell through due to Sega being afraid of Sony's litigation, while the developers of Bleem! simply felt Microsoft wasn't paying high enough for the license for Bleem! (something they had come to regret in the years since).

In the second-floor basement in the nuclear warhead storage-building, there is a miniature Moai Head statue in one of the rooms.

In the Japanese version of the game, the knocked out guard Spoiler:outside of Meryl's cell will still be wearing underwear. In other versions of the game, the guard is found naked with his rear-end blurred out.