The trophy representing Meowth in Super Smash Bros. Melee is a reference to his appearance in a tech demo shown off at Spaceworld 2000 called "Meowth's Party", which itself was based on a recurring ending musical number from the Pokémon anime. In his trophy he is holding the same red guitar that he performs with in the tech demo. The flavor text for his trophy even directly mentions this tech demo:


A version of Meowth's Party eventually made its way into the GameCube release of Pokémon Channel.

Before his career took off as an indie developer, Toby Fox used to play Super Smash Bros. Melee competitively under the old username 'Radiation'.

He is currently the only known competitive Super Smash Bros. player to have a character he has created represented in the series. Alongside the release of Banjo & Kazooie as a fighter, a Mii costume based on Sans from his game Undertale as well as an original remix of the song "Megalovania" were both added to Super Smash Bros. Ultimate on September 4th.

The characters of Captain Falcon, Pichu, Ganondorf, Peach, Jigglypuff, Link, Samus, and Donkey Kong actually have two taunts; one for each direction they are facing (right or left). However, some characters like Donkey Kong, Samus, and Ganondorf have taunts that look identical but actually have very subtle differences that are hard to spot at first glance.

In a March 2002 Nintendo Dream questionnaire with Mitsuaki Hagishima (the general manager of Nintendo's Planning Department), it was revealed that Banjo & Kazooie were planned to be included in Super Smash Bros. Melee as trophies. However, time constraints and the complexity of the approval process (as Rare, the developers of the Banjo-Kazooie IP, were situated in the UK) led to this being dropped, as well as other Rare associated characters (such as Joanna Dark from Perfect Dark) not appearing in the final game. This was brought up again in a September 2009 issue of Rare's Scribes, where it was mentioned that a lot of Rare character trophies were planned to be included in Melee, but it never happened.

Ganondorf's design in Super Smash Bros. Melee is based on his appearance in the Spaceworld 2000 tech demo which showcased a fight with Link and himself where he wields a large sword. This large sword only ever appeared in that tech demo and in one of his win animations in Melee. This specific sword would not be used in Ganondorf's moveset until the release of Super Smash Bros. Ultimate in 2018, where his design is based on that same Spaceworld 2000 tech demo as well as elements from his appearance in The Legend of Zelda: Ocarina of Time.

Starting in April of 2002, the FAQ section of the official website had the question "Are Sonic and Knuckles in the game?".

This was in response to the April 2002 issue of EGM, which jokingly stated that Sonic and Tails could be unlocked by defeating 20 or more Wireframes in Cruel Melee.

Although he appears to be a flat sprite, Mr. Game & Watch is actually a 3D model designed to look 2D from the perspective of the camera.

Both Mach Rider's identity and gender are ambiguous. They are portrayed with a muscular build, and the NES and Famicom versions' manuals never use any gendered pronouns to refer to them. The arcade port Vs. Mach Rider's stage clear screens slowly introduce piece-by-piece an image of a skimpily-dressed woman (bearing similarities to Jane Fonda's appearance in the 1968 film Barbarella) holding a dagger, but it is never specified if this character is Mach Rider, or one of the other wasteland survivors. However, Mach Rider's trophy description in Super Smash Bros. Melee years later lists them as a male character with he/him pronouns. Even later on, Captain Rainbow, a game centered around obscure and neglected Nintendo heroes, has an unused model for Mach Rider that, while not having visible breasts due to wearing armor, portrays them with a feminine skinny waist.

As of 2024, Super Smash Bros. Melee is the only game in the series to not have unique introduction for characters in a VS. match, with every character spawning into the match as trophies. Despite having a timer counting down from three on-screen, it also doesn’t have the announcer counting down from three to start a match, instead saying “Ready…GO!”

King K. Rool's render pose in Super Smash Bros. Ultimate seems to be lifted from an unused character select screen render for Zelda in Super Smash Bros. Melee.

Despite the English version of Melee using Star Fox Adventures' voice cast in the game's Corneria and Venom stages, the Japanese version uses all of the original Star Fox 64 voice actors. Shinobu Satouchi, Hisao Egawa, Kyoko Tongu and Tomohisa Aso all reprise their roles as Fox, Falco, Slippy and Peppy respectively. The former two's voice clips are also used for Fox and Falco as fighters even abroad.

Although Banjo and Kazooie from Banjo-Kazooie would not appear in the series until Super Smash Bros. Ultimate, their names appear as two of the random default names selected in the Name Entry in the Japanese version of Super Smash Bros. Melee. The same is true for Conker from Conker's Bad Fur Day, another Rare character. Notably, Bad Fur Day didn't release in Japan until its Xbox remake, Conker: Live & Reloaded

Captain Falcon has minor gameplay changes based on which alternate skin is being used. Presumably a programming oversight, the character's Environmental Collision Box (ECB), a small diamond that prevents the character from falling through stage environments and walking through walls, differs slightly between skins, meaning they have very slightly different widths for dealing with stage collisions/interaction (although hurtboxes remain the same on all skins). Ranked from thinnest to widest, Captain Falcon's default skin has the thinnest ECB, while the Pink, Blue, Red, and Black skins have wider ECBs, with the Green skin coming out on top with the widest.

If you turn off the music and select Captain Falcon on the character select screen, an extremely faint grunt obscured by the Announcer saying Captain Falcon's name can be heard. In the game's sound test, audio files can be found with "DEMO" attached at the end of them showing that every character in the game had similar planned sound effects on the character select screen, but only Captain Falcon's sound remains audible. Additionally, in the game's files, animations labeled "Select" and "SelectWait" can be found for every character in the game, many of which were either ripped directly from Super Smash Bros., are unfinished, or were repurposed in the final game. These are all presumably remnants of an earlier version of the character select screen that more closely resembled Super Smash Bros., where the character's in-game models were visible and used special animations and sound effects when selected.

There is an unused sound of the Boo's laugh from Super Mario 64 with the file name ST_GREATBAY_TKLE_LAUGH which would've likely been used for Tingle at the Great Bay stage.

In the game's files is an unused sound for when you get a Rare Trophy. This sound would later be used in Brawl, and as part of the character unlock screen in the subsequent three installments following said game.

When the game was rereleased under the "Player's Choice" banner in the US, the color of the game's title on the spine was inverted.

While almost every character requires eight frames after grabbing onto a ledge before they can do anything, Link is the only character that requires four frames before performing another action.

In an animated trailer for Boktai: The Sun Is In Your Hands!, a boy can be heard playing Super Smash Bros. Melee on a Nintendo Gamecube.

There are nine unused event match character tags stored in the game's files. The unused character tags are for Peach, Roy, Pikachu, Pichu, Ice Climbers, Zelda/Sheik, Mewtwo, Ganondorf, and Dr. Mario. They are never seen in game because none of the event matches force you to specifically play those characters.