The laugh of the exploding elf enemies sounds almost exactly like the Boo's throughout the Mario series. This likely due to the clips being similarly sped-up versions of the same stock laugh sound effect.

Six months after the American release of Super Paper Mario, American film director, producer, and screenwriter Seth Gordon, who's most recent works include the Pixels movie had, interest adapting a movie based on Super Paper Mario. Gordon was quoted saying, "I'd love, really love, to adapt Super Paper Mario into a movie, a movie that would constantly switch from 2D to 3D. In five years, 3D cinema is going to be really big." Gordon however specified that he never had the chance to speak with Nintendo about his envisioned project, so his idea was eventually forgotten.

The art of Super Mario Odyssey reveals that Rosalina was going to appear in the game as a none-playable-character in casual attire with a guitar. The book also reveals several unused outfits for Mario, such as the green Sprixie Princess from Super Mario 3D world, a Toadette costume, a costume of a Luma from Super Mario Galaxy, and a costume of Mario in a Japanese school girl outfit.

During the game's opening cut scene, multiple cuts of Peach on the airstrip seem to have an error where the texture for her earrings use the texture for her eyes. This mistake is seemingly fixed from her first close-up onward.

The names of the post-game master trainers appear to be references to other outside media:
•The Pikachu master trainer Lass Iuke is a reference to voice actress Ikue Otani who voices Pikachu in the Pokemon anime.
•The Eevee master trainer Lass Aoi is a reference to Aoi Yūki, the voice actress for Eevee in the game.
•The master trainers for Zubat and Golbat, Scientist West and Scientist Keaton, are references to actors Adam West and Michael Keaton, respectively, who both played the superhero Batman.
•The master bird trainers Bird Keeper Barney, Bird Keeper Seymour, and Bird Keeper Moe, are possible references to the characters Seymour Skinner, Barney Gumble and Moe Szyslak from the animated series The Simpsons.
•The three ghost master trainers: Psychic Arin, Psychic Danny and Psychic Ross, are references to the members of the video game web series Game Grumps; Arin Hanson, Danny Avidan and Ross O'Donovan.

A large area of the game, titled The Boneforest, was cut late in development.

The GameCube version contains Mario, Luigi, and Peach as playable characters. This was part of a deal EA made with Nintendo on using third-party characters for their games.

A physical release of the game had been planned and to be published in partnership with Skybound Games. However on November 10th, 2018, it was announced via the developer's blog that the release had been cancelled due to the process proving to take more work than had imagined, especially since the game's development team only consisted of three people.

In an interview with Junichi Masuda, he stated that the source data for the game was almost lost because the computer that stored the data suffered from a nasty crash.

Stacking 30 goombas is the normal limit in game, but it's possible to stack 200. Going over this amount crashes the game.

Ridley's orange pallet swap is in reference to the villain'a appearance on the box art of Super Metroid.

The license plate on Claire's motorcycle, "J2198", is a nod to Resident Evil 2's original release date, January 21st 1998.

The infamous Red LED lights that surround the 360's power button actually represent different problems depending on how many are alight. One red light meant a hardware failure. Two red lights signify overheating. Three red lights meant a general hardware failure, and four red lights meant and AV cable error. The notorious "Red Ring of Death" is actually, contrary to it's name, a 3-Light problem (General Hardware Failure).

According to Nintendo's Kensuke Tanabe, a horror game starring Tingle began development in 2010. It would've been developed by Vanpool, the developers of the Dillon series. Nothing else is known about the project, except that it was canceled due to "a variety of reasons".

According to a Famicon Tsuushin magazine interview, with Shigeru Miyamoto, the cars in the game hover so that Nintendo didn't have to animate the car's tires.

Found within the game's data are unused themes of the mini-games "Let's Get a Move on" and "Pandemonium" from Mario Party 3 and 9 respectively, suggesting mini-games from Mario Party 3 and 9 that used those tracks were intended to be included in the game.

In the publication "The Legend of Zelda Encyclopedia" by Dark Horse Comics, it was strongly suggested that the entirety of the first legend of Zelda game actually takes place on Death Mountain. Furthermore there are a lot of similarities between the entire map of The Legend of Zelda and the Death Mountain portion of the overworld from The Legend of Zelda: A Link to the Past, giving more credence to the claim.

38 Studios was founded by former Boston Red Sox all-star pitcher Curt Schilling with backing from the state of Rhode Island as a way to help the state's struggling economy. The company only released one game, Kingdoms of Amalur: Reckoning, which was regarded as a commercial failure and the reason behind the company going bankrupt.

There's unused longer versions of each dance jingle used in the game.

When the designs for the first 8 characters (Alice, Snow White, Red Riding Hood, Sleeping Beauty, Cinderella, Pinocchio, Gretel, and Kaguya) were revealed, the notes by the director and author, Yoko Taro, repeated "Very cute! I believe she’ll/he'll sell well!" for each character. When the 9th character (Little Mermaid) was revealed he used his note to directly address his lackluster comments:

"I’ve been commenting my honest feelings of “Very cute! I believe she’ll sell well!” about all the designs we’ve presented up until now, but someone pointed out that “Yoko Taro is really slacking it with his comments.” So this time, please allow me to change the comment to: “If we’re talking cute or not cute, then she’s very cute! If you’re wondering whether she’ll sell well or not sell well, I think she’ll sell well!! But even if she does sell well there won’t be any money in it for me or Jino-san, and I can’t sleep at night thinking about the wonderful people at Pokelabo or Square Enix pocketing the money!”