Despite being a boss character, Master Hand is considered worse than any regular character in competitive play when unlocked through the Name Entry glitch. This is due to his high power and unconventional win conditions being nullified by his lack of defense options, slow attack and non-existent movement speed, and - in the case of doubles - his inability to attack the member of the opposing team with a lower port number.

Due to Master Hand being an undesirable character to play as, he is rarely explicitly mentioned as being banned in Melee tournament rulesets. However, he will usually be banned at a TO's discretion in the rare occasion he pops up, due to his win conditions stretching matches out extremely long and his matches always ending with the game crashing.

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.

There is a glitch that makes Samus Aran's grapple beam three times longer than usual. It is performed by pressing: Z, up, down, up (on the D-pad) and Z.

By pressing the L button, the grapple will also home into opponents, but the A or Z button must be pressed again to grab enemies.

Ness is the only character who can't charge his down smash near a ledge, because his is the only one in the game that has a hitbox while it's charging.

Ayumi Tachibana, from the Detective Club series on the Famicom, was considered for the Super Smash Bros. Melee roster. She wasn't included because the character and the franchise she's in aren't well known outside of Japan.

Wario was originally going to be a playable fighter in Melee but wasn't added due to time constraints. He even had one of the highest potentials of being in the game according to the Smash 2 polls. Sakurai even stated that he would've been included if he had time.

According to early screenshots, the Yoshi's Island stage was originally going to have Jump Blocks.

On the stage select screen, a small 3D preview of the stage that the cursor is hovered over is displayed in the bottom left corner of the screen. Hovering over the "Random" option shows nothing in this space, however it does displayed a model of a tall tilted structure outside of the player's viewpoint. This can only be displayed by altering the game's camera in emulation.