Luigi's voice is just a pitch-altered version of Mario's.

In the character select screen, the characters (excluding unlockable characters) are placed in the order of when they first appeared in their respective titles, starting with the oldest, Mario and Donkey Kong, and leading to the most recent, Pikachu.

While all other characters show their skeletons upon being hit with an electric attack, Samus's suitless outline becomes visible instead.

Captain Falcon is the only playable character that doesn't use his own head for his stock life icon. Instead, he uses a Falcon.

In the background of the Mushroom Kingdom stage, Green Koopa Troopas can be seen walking back and forth across platforms. This contradicts every Mario game to date where Red Koopas turn when coming to an edge while Green Koopas will simply walk off the edge. This would later be corrected with the stage's reappearance in Super Smash Bros. Ultimate.

Captain Falcon's "Congratulations!" screen is the only one to use a pre-existing image from an original game, in this case, the first unlockable title screen from F-Zero X.

When the Announcer introduces Metal Mario, his voice becomes slightly metallic. Although it may just be to place emphasis on Metal Mario's metal composition, the Announcer's voice sounds noticeably deeper and it does not change like that for any other character in Classic Mode.

Captain Falcon has the most usable costumes in the game, with six. Most characters have four or five. Yoshi also has six, but only four are usable outside of hacking, as two only appear in the single player mode.

It is impossible (at least without the use of a cheat device) to clear all eight digits in the points counter in 1P mode.

Charles Martinet is misspelled as Charles Martinee in the game's credits.

According to a page on the Japanese Super Smash Bros. site, Mewtwo was planned to be playable, but was cut; Bowser and King Dedede are also mentioned as having been cut, though no other information is available.

The Fighting Polygon Team is called Dummy Corps in the Japanese version.

For some reason, the announcer says Fox differently in the Japanese version than in the International version, even though Fox is a character with no name differences in any region.

Super Smash Bros. was developed with a low budget, had low publicity when it launched in Japan, and was even intended to be Japan-exclusive. However, the game's success prompted Nintendo to localize it for international audiences.

Captain Falcon and Ness are the only playable characters who do not have a stage based on their respective franchises.

The game's official US website refers to the Bob-omb item as "Bomb Soldier".

Falco Lombardi, Slippy Toad and Peppy Hare were at one point considered for Fox's alternate costumes, before being scrapped in favor of generic recolours. Falco would eventually appear as a unique character in Super Smash Bros. Melee, and while Slippy and Peppy to date still have not appeared, alternate costumes that change a character outright would become a Smash feature starting in the 3DS and Wii U games, with Alph for Olimar, the Koopalings for Bowser Jr, and Alex, Zombie and Enderman for Steve.

When looking for additional characters based on pre-existing fighters to include in the tail-end of Super Smash Bros.' development, Masahiro Sakurai had considered including Clefairy from the Pokémon series as a derivative of Kirby's skeleton. Ultimately, he chose Jigglypuff, as he felt its personality stood out more as a weaker character likely to be defeated.

Despite being boss characters in the game's 1P Mode, Giant Donkey Kong and Metal Mario are competitively considered some of the worst characters in the game and a clear downgrade from their root characters when modded into Vs. Mode.

Mario and his Special Moves in this game are based off of the "Shoto" style of Fighting Game characters, most specifically the character Ryu from Street Fighter. For example, like Ryu, Mario has a Hadoken-like "fireball" attack with his Neutral Special (Fireball), A punching uppercut similar to the Shoryuken via his Up Special (Super Jump Punch), and a spinning tackle akin to Ryu's Tatsumaki Senpukyaku in the form of his Down Special (Mario Tornado). However, while Mario's moveset would change in later games to be less Shoto-esque, Ryu himself would be added into the Smash series and make his debut as a fighter in Super Smash Bros. for Nintendo 3DS and Wii U.