MultiVersus lead writer Eric Stirpē has stated that he writes each fighter as a "Multiversus version" by picking a point in a franchise's history for them to be chosen from by Reindog, in an effort to keep their dialogue in line with the source material. Some fighters from a single franchise are chosen from different time periods within it, but the points when they are chosen are not canon to the source material or the game's plot. It's unknown how every fighter fits into this writing guide, but it creates some inconsistencies with their designs in the game:

• Stripe and Gizmo were chosen just before Stripe's death in the first Gremlins film.
• Finn and Jake were chosen during the events of Adventure Time: Islands, though the lack of Finn's prosthetic arm is not explained, and Fern was chosen before he became a villain in Season 9 of Adventure Time.
• Steven and Garnet were chosen during Season 2 of Steven Universe.
• Bugs Bunny was not chosen, but rather emerged from hiding since the 1940s through a hole in his animation cel or film reel, with him being referred to as a "timeline hopper".
• Taz is from the 1990s (presumably tying him in to Taz-Mania).
• Marvin was chosen during the events of Space Jam: A New Legacy, and LeBron James was chosen two days after the end of the film.
• Tom and Jerry are from the 1960s, but are portrayed with a modern art style that does not resemble either the Gene Deitch or Chuck Jones runs of theatrical shorts from that time.
• Shaggy was chosen one year after the end of Scooby-Doo, Where Are You?, while Velma was chosen from an unspecified "cancelled 2000s reboot".
• The Iron Giant was chosen while returning to America after he re-assembles himself at the end of the film.
• Arya Stark was chosen during either Season 6 or 7 of the Game of Thrones TV series.
• Stirpē considers the DC Comics heroes and villains to all be original interpretations of the characters created for Multiversus.

The first small patch for Crow Country released on May 10th, 2024 merely states "Fixed xenophobic mushroom boys. Ask me about it some time." Tom Vian, technical director at SFB Games, elaborated on this in a Twitter thread stating a bug had been reported through the Steam forums regarding the "mushroom boys" found throughout the game. As it turned out, the config settings regarding the mushroom boys' trigger distance had been stored as text, with said distances using fractional values. This caused issues regarding the computer's native regional style. For example, a French computer would read a "0.4" value as simply "0", making the trigger range impossible to enter. Similarly, a German computer would turn the value into "4", meaning the trigger range could reach halfway across the room. The glitch was fixed by updating the game so that it only used the United Kingdom's configuration settings, as this was how the devs' settings were written, and was why the glitch was never encountered during playtesting (the playtesters were mostly from the UK aside from a few US playtesters).

In the Japanese dub, upon meeting Eiji Mitamura for the first time on the plane, Eiji will tell Ichiban the French phrase "Bon voyage" (usually translated to English as "have a nice trip"). In the English dub, this was changed to the Hawaiian phrase "a hui hou" (translated to English as "until we meet again") to fit with the Hawaiian setting of the game.

There is seemingly an error in the descriptions of the Daidoji Grapple Strike/Grip Breaker moves in both fighting styles. The moves are simple counters for if Kiryu is grabbed, and act as a way for Kiryu to throw the opponent off of him. However, the descriptions for the moves read "When surrounded by enemies", implying a different function for the move.

The hand-operated puppets utilized in Japanese promotional material for the first Star Fox game, as well as the cover of one of its guidebooks, were created by Takashi Yamazaki, a Japanese filmmaker and visual effects supervisor best known internationally for his 2023 film "Godzilla Minus One".

When assets from Star Fox 2 were leaked in the 2020 Nintendo Gigaleak, one character that caught people's attention was what appeared to be a human woman. Some fans and news outlets assumed the character to be black based on her frilly hair and large lips, but palettes were eventually discovered that revealed her to be fair-skinned. The human woman's sprites have the same filename as Miyu and Fay's in the final game, and her two sprites' facial structures resemble Miyu and Fay's prototype sprites (the latter being a sheep instead of a poodle), suggesting she was simply a placeholder meant to give a human reference for Miyu and Fay's anthropomorphic expressions.

In the April 1998 issue of Electronic Gaming Monthly's spin-off magazine EGM2, the issue's Trick of the Month was an alleged method to unlock Akuma from the Street Fighter series as a secret playable character in Resident Evil 2. In order to unlock him, the magazine instructed players to play through both story scenarios six times each using only the Knife and the H&K VP70 gun on hand at the start of the game, and achieve an A ranking in all scenarios. Once these specific conditions are met, the player would receive some kind of clue that would lead them to the security computer in the Laboratory on Level B5F. At this point in either scenario, players would type "AKUMA" instead of "GUEST" into the computer, and after entering it would be sent to the Save screen and given the option to make a new save file with Akuma's name. After starting this new file, the game would start with Akuma breaking out of a cryogenic tank in an unused area where Tyrants were originally planned to escape from, and make his way through the game without the use of keys, with his main attack being a red Gohadoken used just like a gun by holding the Action button and firing.

In reality, after going through these difficult unlock conditions, entering AKUMA into the computer will not unlock anything, because the trick was an elaborate April Fools' prank (with the exception of the unused Tyrant area, that was real). This prank was the work of EGM2 editor and art director Mike Vallas, who took assets from Street Fighter EX and heavily modified and photoshopped them into Resident Evil 2 gameplay screenshots. It was one of two proposed April Fools' pranks that were in consideration to appear in the main EGM magazine that month, being beaten out by a prank trick for GoldenEye 007 where you could play as previous James Bond actors. Unlike Akuma, they actually were planned to appear in that game, but can only be accessed with GameShark codes.

Although Chapter 1 was given a surprise release in 2018, with Toby Fox giving no prior public indications of its existence, Deltarune had been teased in secret since at least 2015. Three months after Undertale released, the fan site DeltaRune.com announced that it would be rebranding to Dreemurr.com at Fox's request; Fox didn't tell the owners of Dreemurr.com why he didn't want them to use the domain. However, after the fan site fulfilled his request, Fox used deltarune.com to host an image called him.png, a passage of Wingdings text only readable by turning up the brightness using image editing software.

While the text initially parroted the phrase "THIS NEXT (space) EXPERIMENT (space) SEEMS (space) VERY (space) VERY (space) INTERESTING" from the unused room_gaster event in Undertale, by July 1, 2016, the text was edited to read "THREE HEROES APPEARED (space) AT WORLD'S EDGE", later being edited again by August 17 to say "THREE HEROES APPEARED (space) TO BANISH THE ANGELS HEAVEN". Both revisions quote portions of the legend that Ralsei recounts in Chapter 1, indicating that these parts of the game's backstory were already conceived by this point.

Following the release of Chapter 1, deltarune.com would be refurbished as the official website for Deltarune itself. Consequently, earlier versions of the site only survive through snapshots on the Wayback Machine, a URL archiving platform hosted by the Internet Archive.

THE JOY OF CREATION is the first and so far only officially endorsed Five Nights at Freddy's project to be developed in Unreal Engine 5, with past games using Clickteam Fusion 2.5, Unreal Engine 4, or other less commonly used game engines.

In regards to the game's visuals, director Ryan Vandendyck opted to avoid using a style that was considered common among indie games, stating:

In 2012, Toby Fox posted several Yume Nikki fan songs to his Tumblr account. One of these, "waltz of seccom masada" (named after a fan nickname for the piano-playing NPC in the spaceship area), bears strong similarities to the Deltarune track "Man" (heard in the hidden rooms where Kris can obtain an egg from an invisible NPC behind a tree), indicating that Fox repurposed and rearranged the song for his own project years later.

In Volume 5 of his Famitsu column "Toby's Secret Base", creator and director Toby Fox revealed that Ralsei's name came from a period in elementary school where he and his brothers constantly experimented with RPG Maker, having long had a shared interest in game development. Fox's oldest brother spent years working on a game called New Genesis, which featured a protagonist named Ralse; Fox simply appended an "i" to the name when incorporating it into Deltarune years later.

In the same column, Fox stated that the prolonged development of New Genesis discouraged him from making games for a long time. When he finally returned to the field in his teenage years, he sought to temper his expectations from the outset by making smaller-scale titles and preemptively planning out his approach to development to avoid biting off more than he could chew.

In a 2008 interview with the game's director Katsura Hashino published in the Persona Club P4 book, he credited the game's Japanese voice cast for having "saved us". He went on to explain the casting process for the Japanese version, which only started after a rough draft of the script was finished. The game's scenario writer Yuichiro Tanaka came up with a list of potential candidates and samples of their work; Hashino, character designer Shigenori Soejima, and sound designer Shoji Meguro selected the cast together from that list. Hashino noted that none of them had much knowledge about voice actors and only relied on the given samples to choose who they felt was best for the role.

At one point when talking to D in The Crooked Man, David reveals that he is color blind, which ultimately lead to him failing to become a pilot. The Boogie Man elaborates on this, revealing that while he can see red, he has difficulty with white and pink. This would suggest that he specifically has Deutan Color Blindness, where it is common to confuse pink and white colors (particularly in cases where the pink is akin to a light purple).

At the very beginning of Appendix v. The Lost Falls, after Ida presses the first switch in the level to raise the pillar the Totem is on up to where she is, a set of symbols carved into two sides of the pillar are revealed. These symbols are part of the ancient Zuish language from the game Fez, but they are used incorrectly in order to fit the message on the pillar (i.e. vertical spelling, no use of spaces, line breaks in the middle of words). When translated, it spells out this message:


This not only acts as a reference to the popular quote at the start of The Legend of Zelda to show Ida receiving help, but also acts as foreshadowing to the end of the level where Spoiler:the Totem is destroyed by a crushing stone pillar while helping Ida get past it, forcing her to go through the rest of the Forgotten Shores levels on her own.

In 2014, developer Danny Gray revealed while promoting Monument Valley at its release that there was a single Easter egg hidden in the main game. It would eventually be discovered and then confirmed by Gray two years later that this secret was in the green room of the main game's final level X. Observatory, where a green model of an Arwing from the first Star Fox game can be found floating near some debris in the bottom-right corner of the area.

Behind-the-scenes pictures from the game's development show that former wrestler Jeff Jarrett did green screen capture work for appearing in the game as a playable character. However, due to his departure from the WWF (now known as the WWE) in 1995 regarding a contractual dispute before the game's release, he was subsequently removed from the roster.

In The Murder of Sonic the Hedgehog, when Sonic is found presumed dead on the ground, the pose he is laying in is a reference to a meme within animation circles known as the "Family Guy Death Pose". This pose is frequently used throughout the animated series of the same name created by Seth MacFarlane, which became criticized in later years for utilizing cheaper animation. This is not the first time this pose was referenced in the Sonic the Hedgehog franchise; the first time being in Issue #3 of the IDW comic book miniseries "Sonic the Hedgehog: Imposter Syndrome", where the character Surge collapses into the pose at one point.

In 2022, the English rock band Arctic Monkeys released a song titled "Sculptures of Anything Goes", featuring the following lyric in the last verse of the song:


This lyric became the subject of news articles when fans on the music lyrics website Genius initially determined that it was referencing the obscure Nintendo DS game City Life DS, which only released in France in 2008 and the United Kingdom in 2009, and did not sell as well as previous games in the City Life series. Fans theorized that the difficulty in finding a copy of the game referenced in the lyric stemmed from Nintendo eventually discontinuing the DS family of systems to support future consoles. They also cited the closure of the Nintendo 3DS/Wii U versions of the Nintendo eShop as another possibility, but this was unfounded as City Life DS was only officially released as a physical cartridge and not part of the Wii U Virtual Console's Nintendo DS library.

However, it was confirmed in an interview with the band's frontman Alex Turner by Rolling Stone Germany on the day the song released that the lyric was not about City Life DS. He attributed the lyric to the works of author David Foster Wallace, most likely as a reference to his book "Infinite Jest" where the characters consume entertainment in the form of cartridges, which could also be referring to Turner's growing struggle to appeal and relate to Arctic Monkeys' audience from their earlier years as their sound and image changed later on.