If you allow Mario to fall asleep (by remaining idle for an extended period of time) for long enough, he'll start sleep-talking about spaghetti and ravioli, two Italian foods.

The enemy Blargg from Super Mario World is found in the game's code, but it's model and programming are unfinished. It has an animation for jumping out of lava, but doesn't do anything else.

In the mission "Blast to the Stone Pillar" in Jolly Roger Bay, the Power Star is contained within a box in the Western versions of the original game, but not in the Japanese version. This was likely changed during localization to make the star's position less obvious. However, all versions of the Nintendo DS remake leave the Power Star out in the open.

In the world "Bowser in the Sky", two Goombas can be seen on the same platform together. These two Goombas are actually part of a Goomba trio object loaded by the game, however, the third Goomba is placed over the edge of the platform, resulting in it rendering at the bottom of the stage, out of reach.

The Japan-only Shindou Pak Taiou edition of the game contains an exclusive Easter Egg on the introductory screen: pressing Z fills the background with images of Mario's face. These images are taken from the frame buffer, and therefore reflect the current state of the 3D model of Mario's head that the player can manipulate.

Early in development, before Charles Martinet was hired to provide Mario's voice, the developers used stock Looney Tunes voices as placeholders.

The Big Boo in Big Boo's Haunt course originally held a key instead of a Power Star inside of him. The keys would unlock the various doors in Big Boo's Haunt. There was even a key counter to display how many keys the player had acquired.

There is a metal wing texture in the game for combining the Wing Cap and Metal Cap, similar to how the Vanish Cap and Metal Cap can be combined in Dire Dire Docks and Wet Dry World. There are no levels in the game where it would be possible to equip both simultaneously, but they do function and use this texture if given to Mario via hacking.

There is a glitch that causes Mario to hold his hat in his right hand. This occurs when Mario picks up two hats in rapid succession. If Mario loses his hat in Snowman's Land by being blown away by the giant snowman's breath, and then takes the warp under the tree, his hat will duplicate, and retrieving it will cause this glitch.

Two small Koopa Troopa shells, one green and one red, can be found in the game's data. Both of these shells are the same sizes as Spiny shells, however, they cannot be used.

The second Power Star on Cool Cool Mountain, acquired by reuniting the baby penguin with her mother, appeared over the mother penguin's head in the Japanese version. It was moved next to the pool in other releases, likely to make it easier to obtain.

Princess Peach doesn't have any voice acting in the original Japanese release during the beginning and final cutscenes. This was added for all other versions.

Several of Mario's voiced lines didn't exist in the original Japanese version of the game, and were added for western releases:

• "Hello" and "Press Start to Play" during the demo screen with Mario's head.
• "Okey-dokey!" when choosing a save file.
• "Let's-a go!" when choosing a star.
• "Game over." when Mario runs out of lives.
• His dreams about pasta are missing.
• "I'm-a tired." - when the player is idle.
• "So long-a Bowser!" - when Mario throws Bowser a long distance.
• "D'oh!" - when long-jumping, sliding, or diving into a wall.
• "Boing!" - when bouncing off of a Spindrift's head.
• Mario will say either "Yahoo!", "Wha-ha!", or "Yippee!" during the last jump in a triple jump. In the Japanese game, he says "Yahoo!" every time for the third jump.
• In the opening sequence, Mario says "Yahoo! Ha ha!" when he leaps out of the pipe instead of just "Yahoo!" in the Japanese version.
• Mario will always say "Mama Mia!" after being ejected from a level's entrance after losing a life, unlike the Japanese version where he only says it when ejected from a portrait.

The Idea for Metal Mario may have come from an interview with Shigeru Miyamoto published in 1991, in Nintendo Power's Mario Mania Player's Guide, Miyamoto reportedly said: "Who knows what Mario will look like in the future? Maybe he'll wear metallic clothes!"

In a 1996 interview with Shigeru Miyamoto published in Super Mario 64's first Japanese strategy guides, he revealed that Mario's running animation, speed and movements in that game were influenced by Arale, the main protagonist of the 1980 Akira Toriyama manga/anime "Dr. Slump":


However, Dr. Slump's influence throughout the Mario series could trace back even further. Some particular examples from Mario games include:

• His running speed, animation, the Racoon and Tanooki Suits from Super Mario Bros. 3
• The Wing Cap from Super Mario 64
• The Cat Suit from Super Mario 3D World

Even traits of Mario's happy cartoonish personality, his short stature and gloves, and blue-red-overalls color scheme bear enough similarities that they all could have been taken from Arale's appearances and other elements throughout Dr. Slump. Despite this, outside of Miyamoto's comment, these connections are not known to have been elaborated on by any other employee from Nintendo.

Although the Headless Snowman is a minor character in his few appearances, he received some publicity in the form of a Nintendo Power joke published around the time of the main circulation of the "L is Real 2401" Super Mario 64 rumors.

In Volume 107 of Nintendo Power, in the April Fool's-themed "April News Briefs" segment, a "Luigi 64" article is present, where Nintendo states that Luigi fans had been campaigning to have the character in his very own game, and the company's response was to create a hoax upcoming game known as "Headless Snowman 64". This game was apparently intended to satisfy fans of the "second bananas" by featuring a cast of both well-known and obscure Nintendo characters, with the obscure characters including the Wave Race 64 announcer, "random audience members from Super Punch-Out!!", "the frogs in the meadow" from Diddy Kong Racing, and the Headless Snowman himself. Additionally, the game would supposedly contain some non-Nintendo characters such as "that bald guy from Blast Corps," and "the bikini woman in Cruis'n USA." Humorously, this never-made game was not going to feature Luigi, with a developer comment at the end of the article confusing him for "one of the civilian women in GoldenEye 007".

In an interview with Satoru Iwata and Shigeru Miyamoto, it was revealed that an early, experimental build of the game had split-screen multiplayer, with Mario and Luigi as playable characters.

The game's planned multiplayer mode ended up being reworked into a Mario Bros.-style minigame thanks to the Nintendo 64's technical limitations making the split-screen concept unfeasible. However, in February of 1996 (just a month before E3 of that year), both multiplayer mode and Luigi were removed, in part because the Nintendo 64 was bundled with only one controller. These statements are corroborated by findings from the Gigaleak, a massive content leak of internal data from Nintendo in 2020 that included early assets from Super Mario 64. Among the leaked material was a model and textures for Luigi and sprites for "1P" and "2P" icons. Luigi's model is dated June 20, 1995, while the icons use the same generic font seen in the Shoshinkai demo from November of that year, rather than the custom font seen in both the E3 1996 demo and the final release.

In the castle courtyard in Super Mario 64, there is a plaque to a power star with an illegible name written below, often interpreted as either "Eternal Star" or "L is Real 2401" - with the latter being more popular for how it could be seen as a cryptic hint towards unlocking Luigi.

In a poetic coincidence, the source code leak that revealed Luigi's scrapped model would be found 24 years and 1 month after Super Mario 64's release.

The title of "first 3D platformer" is often erroneously given to either 1996's Super Mario 64 or 1995's Jumping Flash!. Despite this, neither game can factually claim that title, with 1990's Alpha Waves being the true owner of the title according to Guinness World Records.

Additionally, 1984's I, Robot - while primarily a shooting game - did feature 3D platforming segments.

The audio used for Bob-ombs, Monty Moles and Goombas in various games starting with Super Mario 64 is actually pieces of Mario's voice saying "Here We Go" from said game after being pitch-shifted. This would continue being the case even after Charles Martinet was replaced with Kevin Afghani starting with Super Mario Bros. Wonder.