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 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.

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.

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.

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.

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.

The bonus for getting a Star KO on all of the opposing team's members is called "Rocket KO". This may be a reference to Team Rocket from the Pokemon TV show, as they are commonly seen blasting off into the sky, punctuated by a star glint.

The reflections found on the Fountain of Dreams and the models inside the magnifying glass when a character is offscreen are not actually the character's model, but rather a low res version of the model. These versions of the models don't show any item the character is holding, nor do their facial expression change.

Like the original Ice Climber, Topis were changed from seals to yetis due to the controversy of seal clubbing. Oddly enough, the English trophy description is exactly the same as in the Japanese.

When the game was revealed during E3 2001, the game's introduction sequence was played, followed by gameplay footage demonstrating each character's movesets. The only changes made when adding this into the game was to the gameplay footage.

In the PAL version of the game, the Rainbow Cruise stage is renamed to "Rainbow Ride", likely for consistency with the international versions of Super Mario 64.

The only fighter who didn't make their playable GameCube debut in this game is Luigi, who was previously playable in Luigi's Mansion.

A segment of the remixed DK Rap used in the Kongo Jungle stage has the Character Select theme from the original Super Smash Bros. mixed into it.

The Ice Climbers' Target Test Room only has Popo (or Nana depending on the color) and instead of the Target Test music, it plays the Ice Climber music. This could reference the game Ice Climber, as Popo climbs to the top alone (unless there's two players), along with breakable blocks and scrolling clouds. The condor appears holding the last target which is referencing how an Ice Climber needs to grab onto the condor at the end of a bonus stage (which Target Test also is). The targets could also reference the vegetables in Ice Climber that the player needs to collect for points.

Roy's belt buckle has the image of a lion on it. This is likely a reference to his endgame title of "Young Lion" in Fire Emblem: The Binding Blade. He was also referred to by this title in the Fire Emblem Awakening DLC.

8-Player Smash (a mode introduced in Super Smash Bros. for Wii U) was originally planned for this game. However, due to technical performance, Sakurai stated "it was more than impossible."

In a prerelease build, the "Temple" stage originally had an elevator that led to the bottom of the stage, and had a fixed appearance. Players could also walk through the laboratory in Great Bay. Hyrule Temple had two mysterious platforms in the center of the stage. These platforms can also be seen in the game's Special Movie.

In the Mushroom Kingdom stage, pausing the game and looking off to the left or right of the stage to see outside of the standard gameplay field of view, it's possible to see walls with warnings signs reading "Danger" on them, warning the player of the stage's boundary. Despite the Mushroom Kingdom stage having a different design in Super Smash Bros. Melee, these signs still appear in the stage.

The last sentence of Pit's Trophy description reads, "Will Pit ever fight again?", possibly foreshadowing his role as a playable character in the next entry of Smash Bros. released 7 years later, Super Smash Bros. Brawl.