Nintendo initially planned to give the Game Boy Advance a large-scale release in mainland China through their subsidiary in the region, iQue. However, they ultimately pulled out following rampant piracy of the system's first few Chinese releases. Consequently, Chinese localizations of several other games were cancelled despite being mostly complete and sent to the Chinese government for review. On March 25, 2019, game preservationist collective Forest of Illusion would leak twelve of these Chinese-language builds online, covering the following games:

• Advance Wars
• DK: King of Swing
• Densetsu no Starfy
• Densetsu no Starfy 2
• Famicom Mini Collection
• Fire Emblem: The Binding Blade
• Kuru Kuru Kururin
• Kururin Paradise
• Mario & Luigi: Superstar Saga
• Mario Kart: Super Circuit
• Polarium Advance
• Tomato Adventure

Near the end of Crab Cove is an inaccessible teleporter only viewable by standing on the bridge above it and ducking for long enough to pan the camera down. Hacking the game to make this teleporter accessible reveals that it simply returns the player to the beginning of the level.

In 2024, a demo build from Kingdom Hearts III's May 2018 Premium Showcase was leaked online. Within the code, a list of worlds featured in the game was discovered, revealing that a world based on the 2006 Pixar film Cars was planned, but did not appear in the final game.

In Alpha Labs, Sector 1, Jack T. Smith's PDA can be found containing an email with the subject line "Buddy system?!". In the email, Smith complains about a newly-implemented buddy system by the UAC corporation in response to industrial accidents. A victim, Joe Moss, is referred to by the nickname "TorsoBoy" because his arms and legs were severed by the "Albuquerck Capacitator". Both his nickname and the name of the machine are references to the lyrics of the song "Albuquerque" by comedy musician "Weird Al" Yankovic.

Within the game's data are unused splash screens for almost every level, with the exceptions being "Neighborhood Nightmares", "Rollercoaster Boss", and "Final Boss". Of note is that the splash screen for "Bat Outta Heck" uses a placeholder graphic, featuring the screen for "Sideshow Spectacular" with "BAT Outta Heck Loading" written on top in Comic Sans. In the final game, every level uses the same generic loading screen depicting the Jimmy Neutron logo and an animation of one of the atoms from the original TV show's opening, with the only differences being the level names themselves.

The notice that Curly receives from Pony Express during the flashback sequences is fully written despite the game's low resolution making it illegible in normal circumstances. Hacking the game to remove the resolution filter reveals that Spoiler:Curly was due to be promoted following the layoff of the Tulpar crew, a detail that is otherwise never revealed in-game apart from vague mentions of Spoiler:Curly being the only crew member who can financially support himself after the layoff.

One of the CPU-only characters in M&M's Kart Racing is a female anthropomorphic fox named Foxy. This character's design bears a striking resemblance to a character named Foxy Roxy from the 1994 fighting game Brutal: Paws of Fury. The copyright holder of the game at the time of M&M's Kart Racing's release is unknown, but one possible candidate is Take-Two Interactive, as it acquired "certain software games" from developer and publisher GameTek after they went bankrupt in 1997. There appears to be no overlap in the two games' development staff, companies, or rights holders, so assuming that the design similarities are not a coincidence, Foxy may have been used in M&M's Kart Racing illegally under the assumption that Brutal: Paws of Fury was an orphan work.

The unreleased Sega Genesis version of Waterworld contains a god mode cheat code activated with the code "ATADNGISED". When spelled backwards, this reads as "DESIGNDATA" and refers to Data Design Interactive, who allegedly served as an uncredited "ghost developer" on the port, despite their logo appearing at the start of the game. The hidden credit may have been added as a failsafe in case the intro credit was removed in development.

In Nickelodeon All-Star Brawl 2, Korra has three neutral specials selected based on the context of their use: a water projectile in the air, a non-offense based slippery puddle on ground, and a torrent of damaging water that goes up and down when used with Slime, regardless of location. This move was originally going to function like it contained three extra special moves in the place of one, where you could do another direction input after starting the move to choose a form (not unlike like Gerald's down special move in the final game). When the move was reworked due to its complexity, it was decided to "shuffle around the pieces" into something more easily understood to avoid wasting finished animations and props and having to make new animations close to the deadline.

There is a voice line said by Knuckles in Sonic Heroes where he exclaims "shift!" while using Sonic and Tails as weapons; this has often been misinterpreted by fans as Knuckles saying "shit!" According to Knuckles' former voice actor Scott Drier, Sega intended for it to sound like that. He claimed that he was intentionally voice-directed by members of Sonic Team overseeing the recording session to say the "f" in shift rather softly so it could be misinterpreted as "shit" in certain circumstances.

During E3 2018, it was announced that Mr. Game & Watch's moveset would be visually updated to more closely resemble its original Game & Watch inspirations. While the design of his forward smash attack was first shown to be the same from the previous Super Smash Bros. games, it was eventually replaced with an original sprite from the game Fire Attack, depicting him as a stereotypical Native American with an angry expression and a feather in his hair (the original context in Fire Attack being that a tribe was attacking a cowboy's fort that the player needed to defend). This change was criticized by some for its portrayal of a racist stereotype, and it was pointed out that this depiction had previously been censored when the game was included in Game & Watch Gallery 4. After being questioned about it, Nintendo released an official apology and removed the feather from the attack animation in a Day 1 patch.

Super Pool III was originally designed as an erotic game. Consequently, in the Japanese version, the title screen features a bunny girl who gets gradually stripped down, while the player's opponent in each level will remove more of her clothes the better they perform. The international release removed almost all of these elements in order to secure a wider audience, with the exception of the bunny girl's accompanying voice clip on the title screen.

On October 15, 2022, Bayonetta's original voice actress Hellena Taylor (who was replaced by Jennifer Hale in Bayonetta 3) claimed that the reason she did not reprise her role was because she was offered only $4,000 for the part, and urged fans to boycott the game's release, prompting responses from various parties involved. Series creator Hideki Kamiya called her statements "untrue, sad and deplorable" and temporarily deactivated his Twitter account after arguing with and blocking fans over his comments. Hale and other actors expressed support for fair compensation for actors while urging fans to keep an open mind about the work put into the game. PlatinumGames issued a statement themselves asking people to refrain from disrespecting Hale or anybody else involved with the series.

However, the story took a turn when Bloomberg released their own report on the controversy three days later. According to the report, PlatinumGames had planned to rehire Taylor with a payment range between $3,000 and $4,000 per recording session for five sessions, which was above the minimum SAG-AFTRA union rates. Taylor had requested a six-figure payment and royalties instead, and refused an offer to make a cameo for the fee of one session once Hale was cast. After it was published, Taylor claimed on Twitter that the report was a lie, but in the process of explaining why, she ended up contradicting her original claims by confirming two key details from the report. She now claimed Platinum's initial offer to her was $10,000, before later being offered an additional $5,000 after she reached out to Kamiya. She also stated that she did not hear back from Platinum for eleven months after this, before being given a final offer of $4,000 to "voice some lines". This means she had actually been offered upwards of $15,000 to reprise the role, and that the final offer of $4,000 was for a cameo. Taylor appeared to have done all of this under the incorrect belief that Bayonetta was a massive franchise with a total revenue of $450 million excluding merchandise sales, resulting in a wave of fan backlash against her for lying by omission to start a controversy based on this misconception.

This is the first game in the Mario & Luigi series to not have music composed by Yoko Shimomura, instead being composed by Hideki Sakamoto. According to an interview with Famitsu, this was done as part of the team's efforts to give the series a "fresh start". However, making new music proved to be a challenge, with series creator Shigeru Miyamoto commenting that the music Sakamoto had originally written for the game sounded "too ordinary". This led to the composers adding more bass into the game's score in an effort to incorporate more "Mario-ness" into the soundtrack.

In the Nintendo Switch port, references to drugs are censored by referring to them as "magicals" and "sweets." Consequently, several drugs that Ame can take throughout the game are renamed to fit this theme, though their function as stand-ins for real-world prescription, over-the-counter, and recreational substances are unchanged:

• Depaz (Prozac antidepressants) is renamed Magical Macarons.
• Dylsem (Deslym cough medicine) is renamed Magical Cookies.
• Embian (Ambien) is renamed Magical Cake.
• Magic Grass (marijuana) is renamed Magical Cigarettes.
• Magic Paper (LSD) is renamed Magical Candy.

Similarly, all instances of the words "sex" and "sexy" are replaced with a row of hearts (though all other instances of sexually charged language and sexual content are unchanged). It is unknown if the changes were requested by Nintendo or if they were done at the behest of the Computer Entertainment Rating Organization (CERO) to permit a console release.

In the South Korean release of the game, the character sprites in "Samurai Kirby" are edited to remove Japanese cultural elements. These changes are owed to widespread anti-Japanese sentiment in South Korea following a 35-year period from 1910 to 1945 where the Korean peninsula was occupied and culturally assimilated by the Japanese Empire. After this period ended, Japanese cultural imports were banned in South Korea for almost 60 years, and while most restrictions were gradually rescinded by 2004, some remain in place.

The 2000 manga adaptation of The Legend of Zelda: Ocarina of Time features a race of bird-like humanoids called the Watatara. According to series producer Eiji Aonuma in a 2005 interview with the magazine Nintendo Dream, the Watatara later inspired the Rito, a similar race of bird people that debuted in The Legend of Zelda: The Wind Waker.

Several unused sprites for an Acorn Baki exist within the game files, including various hurt sprites. This suggests that enemies were originally going to use sprites in the game's levels, rather than the digitally-drawn "toys" used in the final game.

Within the game's data is an incomplete cutscene depicting Anton interrupting Satan's game of Pachinko; the sequence is fully animated and voice acted, but lacks sound effects. The sign on top of the Pachinko machine, "PaFREAKO," indicates that the cutscene was likely intended to precede the Freako Dragon fight.

Meat Boy from Super Meat Boy makes cameo appearances in the World 3 level Gall Blaster and in that world's boss, The Source. His appearance is further addressed in the game's final cutscene where he is shown alongside multiple original characters, teasing Bit.Trip Fate. As a result, the Wii version of the game marks Meat Boy's first appearance on a Nintendo console, as Super Meat Boy would not be ported to one (the Wii U) until six years later.