On December 6th, 2020, an Itch.io user revealed that the game files contained a sprite sheet for Lucky Boy, the titular main character of the 2021 animated short film "LUCKYBOY" as well as an associated audio file called "vidyagames.ogg". This file was actually a low-quality version of the song "Video Games" by the band Black Out Band with a song length similar to that of the game's official songs. Upon this being shared, the game's creator and co-director ninjamuffin99 revealed these were added to the game by his friend Brandy and that they would both be removed as they were not meant to be part of the final game. Lucky Boy's animations were made by Dylee Dee, the 2D animation director for the "LUCKYBOY" short, with some of them (such as the tumbling animation) being used in the film.

In a livestreamed playthrough of Chapter 1, Dratula's voice actor, Twitch streamer and YouTuber Vinny Vinesauce, indicated that his dialogue was recorded with little context regarding when and where his lines would be spoken. Consequently, despite the volume of material provided, he did not realize that Dratula would be the first character that ENA encounters until he played the game for the first time on-stream.

On March 12, 2024, Shiro Project's enhanced relaunch "Shiro Project:RE" expanded their collaboration with the Danganronpa series to include new sprites for several of the series' female characters. Notably, one of the featured characters added was Mukuro Ikusaba, marking the first time she had received new sprites that did not have her Spoiler:disguised as her sister Junko Enoshima.

Ed, Edd n' Eddy: The Mis-Edventures uses gameplay concepts from an unreleased Nintendo GameCube and Xbox game called Pickles, particularly the idea of a team of characters stacking atop one another's heads. According to former Santa Cruz Games director and artist "Tiki" Andrew Webster, an unspecified producer on Ed, Edd n' Eddy: The Mis-Edventures (nobody in the game's credits is credited as a single producer on the development side) met the team behind Pickles at the 2005 Game Developers Conference and fell "head over heels" for the concept of the latter game. Webster claimed that after the former game's release, the developers of Pickles "confronted" the producer at a bar one night and confessed to taking the concept from Pickles before it could be released.

One of the bonus downloadable animals Blue Fang developed and released for Zoo Tycoon was the mythical Yeti, although there is evidence that it was originally planned to be an unlockable Easter egg animal in the base game, similar to the Unicorn and Triceratops. An unused cheat code exists where the Yeti would have been unlocked by naming an exhibit "Kathmandu", the name of the most populous city in the landlocked South Asian country of Nepal located in the Himalayas, where the Yeti was purported to have inhabited in legend.

Mumbo Jumbo, a recurring character within the Banjo-Kazooie series, was originally planned to appear as an NPC in Viva Piñata as evidenced by concept art and a 3D model shown off by the character's creator Ed Bryan.

The Sega Saturn port contains a single Redbook audio track on the game disc consisting of a discordant, high-pitched noise. Slowing this clip down to 15% of its original speed reveals that it is actually a poor-quality clip of a voice speaking indistinctly before a lengthy guitar riff plays. Because this track is not used anywhere in-game, it is unknown whether it is a leftover from development or if it was deliberately included as an Easter egg.

When asked for his opinions on the popular webseries Skibidi Toilet using assets from Half-Life 2 while being aimed at an audience younger than the game itself, Half-Life series writer Marc Laidlaw claimed that he did not mind, because he felt no connection to the characters since he did not create their models. However, he felt that other developers who worked on the game may disagree:


Laidlaw compared the G-Man's sudden popularity through Skibidi Toilet to other pop culture figures from his youth who were also taken out of context from earlier works, particularly Alfred E. Neuman, the mascot of MAD magazine taken from advertisements 58 years older than the magazine itself.

The pieces of the phone can be read cryptically as the letters "HSW", the initials of the game's designer Howard Scott Warshaw.

Due to complaints from various Japanese government officials, including House of Councilors member Hiroyuki Kada and Prime Minister Shigeru Ishiba, Ubisoft released a day-one patch that removed the ability to destroy certain objects within temples (i.e. a shrine modelled after the real-life Itate Hyozu Shrine, the representatives of whom were not consulted about the inclusion of), and reduced the amount of blood shed by NPCs within said temples. These complaints were made out of concern that the in-game destruction would encourage vandalism at real-life temples and shrines.

Hidden in the files of the game's arcade version is an unused character named Blodia, a reference to the giant robot piloted by Jeff Perkins in Capcom's Armored Warriors and Jin Saotome in the spin-off game Cyberbots: Fullmetal Madness. The character is unfinished, sharing its moveset with Gamof. Unusually, instead of looking like the Blodia, its appearance is that of a MS-09R Rick Dom from the 1979 anime "Mobile Suit Gundam".

Several textures in Mega Man Legends 2 contain leftover unused portions filled with the designs of Mobile Suits from the 1979 anime "Mobile Suit Gundam". These include:

• An MA-04X Zakrello hidden in Mega Man's textures
• A RGM-79 GM hidden in Roll's textures
• An MSM-04 Acguy in Barrel's textures
• An MSM-10 Zock hidden in Gatz's Forbidden Island sprites

The chef featured in Personal Trainer: Cooking goes unnamed in both this game and his later appearances in the Super Smash Bros. series, but he actually does have a name. In 2009, Club Nintendo released a CD called "Touch! Generations Sound Track" as a physical reward in Japan, featuring a track from the game titled "Welcome to "Bistro Pierre"". Composer Toshiyuki Sudo confirmed in the CD's liner notes that Pierre is the chef's name.

In Marisa's storyline, Remilia Scarlet responds to her question "How many people's blood have you sucked until now?" with the taunting counter-question "Can you remember the number of times you've eaten bread?" Marisa then responds that she's only done so thirteen times due to her preference for Japanese food. This parodies a similar exchange between William A. Zeppeli and Dio Brando in the 1987 manga JoJo's Bizarre Adventure: Phantom Blood.

In response to a comedic tweet about pirating indie games using Ultrakill as an example, the game's creator Arsi "Hakita" Patala expressed support for piracy among those in situations like poverty. He noted that Ultrakill only came to be thanks to inspiration from works that he pirated in his youth, and encouraged supporting a game via word of mouth as an acceptable substitute for a purchase, saying: "You should support indies if you can, but culture shouldn't exist only for those who can afford it."

The game was first announced as "Marvel vs. EA", in reference to how it featured several iconic Marvel characters going up against a group of original characters created by Electronic Arts. In March 2005, the game's final title was revealed, as well as the involvement of comic artist Jae Lee and designer Paul Catling in the creation of EA's original characters, the titular Imperfects. This game and the 2005 promotional tie-in comic "Marvel Nemesis: The Imperfects" are their only major appearances in any Marvel property to date, likely because of the game's poor reception. While it was previously thought that EA owned the rights to the Imperfects since they created them, comic book writer Jonathan Maberry revealed in 2012 that Marvel actually owns the rights to them.

The Japanese manual for Sonic & Knuckles alludes to the game's Special Stages in its story section, which includes a moment where Sonic gets sucked through a Super Ring and arrives at the Master Emerald Alter, where the player accesses the Special Stages in the game. However, writer Ian Flynn would later claim the Special Stages seen throughout the series are not considered canon, instead only existing as a gameplay mechanic.

According to former Mojang business and production director Daniel Kaplan, he came up with the original name for the mobile version of Minecraft, "Minecraft: Pocket Edition", a nod to the Game Boy Pocket, because he was a Nintendo fan.

To promote Pokémon Black and White, the Pokémon Company partnered with alternative rock band The Presidents of the United States of America to create a song titled "Can't Stop (Catchin' 'Em All)". The song mentions a multitude of Unova Pokémon alongside brief descriptors of their behavior or appearance. A music video was also created that was shared online and on a promotional DVD given out through Nintendo Power magazine. In addition to some of their original songs, the band performed "Can't Stop (Catchin' 'Em All)" live at the Pokémon Black and White launch party on March 5, 2011 at the Nintendo World store in New York City.