The version of Panel de Pon included on Nintendo Puzzle Collection was originally intended to be released on the Nintendo 64 in Japan, and a prototype featuring the Panel de Pon fairy characters is known to exist. It did see release on the console in other regions as Pokémon Puzzle League, however.
Hard 'n' Heavy was originally conceived as a sequel to The Great Giana Sisters titled Giana 2 - Arthur and Martha in Future World, but was changed due to the threats the developers had received from Nintendo over the previous Giana game. Screenshots and a box art for Giana 2 exist, and show that seemingly only the character of Giana was removed in the transition to Hard 'n' Heavy, but the version of the game with Giana is not known to exist.
Based on evidence from the book Video Game Quest and unused graphics within the game's code, Snoopy's Magic Show was likely originally going to be an original IP, with the title of either Death Ball or Heart Attack.
According to the British magazine Nintendo Magazine System, before settling on Yoshi's Island characters for Tetris Attack, Nintendo reportedly asked Rare to replace Panel de Pon's fairies with characters from the Killer Instinct series.
Yoshi's dialog in Tetris Attack was not rewritten from Lip's dialog in Panel de Pon to account for the dinosaur's more laid back, cheerful personality, resulting in him saying rather stoic fantasy hero lines such as "Together we own our world" or "We can't just be strong, we must be strongest".
Alex Kidd: High-Tech World revolves around Alex going to a new Sega arcade called "High-Tech World", which seems to be a strange and arguably counter-intuitive product placement for Sega's Hi-Tech Land arcades that only existed in Japan and have a slightly different name from the one given in the game. The game was originally released in Japan as Anmitsu Hime, and revolved around finding a cake shop instead of an arcade, meaning that the audience that could actually have a Hi-Tech Land in close proximity would not be able to play the game under normal means.
The Sega Retro article for Hi-Tech Land (https://segaretro.org/Hi-Tech_Land_Sega) claims the name to have originated after High Tech World's release in 1989, but the wiki itself has two contradicting pieces of evidence:
Yogi Bear: Great Balloon Blast contains a fully functional unused character in the form of a duo of Dexter and Dee Dee from Dexter's Laboratory, a Hanna-Barbera cartoon that was still airing at the time. It is unknown if this is a remnant of a scrapped Dexter's Laboratory version of Pop'n Pop, much like Dexter's Laboratory: Robot Rampage was for Elevator Action EX, or a scrapped plan to make the game a Hanna-Barbera/Cartoon Network crossover game.
When Elite Software obtained the license to make a video game based on the ThunderCats cartoon, they were unsure if they would be able to complete the game in time for Christmas, and as such outsourced a second ThunderCats game to Paradise Software. Neither game could be finished before the deadline, and as such Elite instead attained the rights to a near-finished game titled Samurai Dawn by FTL Games and released it as ThunderCats: The Lost Eye of Thundera.
Elite's in-house ThunderCats game got pitched to Capcom as a sequel to Ghosts 'n Goblins, but was not picked up due to Ghouls 'n Ghosts being in development at the time. It would be released as an original IP, simply titled Beyond the Ice Palace, featuring a character who in certain versions of the game resembles Lion-O.
Paradise Software's ThunderCats game remains shrouded in mystery, but it seems incredibly likely that the game was released as Bomb Jack II, owing to the C64 version of the game including a rendition of the ThunderCats theme song (stolen music being somewhat of a tradition for the Bomb Jack franchise), not featuring any bombs, and having a protagonist that more closely resembles Lion-O than Bomb Jack.
According to designer Norio Okubo, Wario Blast was originally going to feature Mario instead of Wario - this was changed due to cultural sensitivity regarding bombs in certain regions, where it was decided that having a villain like Wario plant bombs would be seen as more appropriate than if a hero like Mario were to do so.
Expresso the Ostrich from Donkey Kong Country appears as a cameo in Banjo-Pilot - this seems to be an accidental leftover from the game's cancelled iteration as Diddy Kong Pilot, as Nintendo is not mentioned whatsoever in the copyright info for Banjo-Pilot beyond simply licensing the game for its platforms.
As stated in the game's official app store description, Blue Ninja is intended to be a parody of superheroes and "the best of ninja trained spider games". Based on the initial teaser trailer (when it was known as "Superhero Game 2021") featuring a different red and black design from the final game, using music from the film "Spider-Man 3", and the game description's numerous references to "spider heroes", it's very obvious that this game is meant to specifically be a parody of the Marvel Comics character Spider-Man. The visual similarities to Spider-Man in Blue Ninja's early design were most likely changed for the final game to avoid copyright disputes.
Name This Game was a gimmick release with a self-explanatory title. Originally conceived as a Jaws game for Parker Brothers, it was rethemed with an octopus for Quaker Oats' U.S. Games branch after the license fell through - while U.S. Games originally intended to release it under the name Guardians of Treasure (a combination of creator Ron Dubren's suggestions of Guardians of the Deep and Treasure of the Deep), it was decided to make the game's name the subject of a contest where players could win $10,000 for providing a title for the game. U.S. Games was dissolved by Quaker Oats before the name could be chosen, leaving the game without an official title.
Tails' Skypatrol was originally developed as a licensed Disney game for an unreleased budget handheld system aimed at a younger audience with a focus on educational content - much like Sega's Pico - and was reworked into a Tails game for the Game Gear after the console was scrapped, due to the Game Gear's similar stats to the unreleased hardware. It is not known which Disney character Tails replaced, however a pre-release promotional video shows the Mickey Mouse character Peg-Leg Pete in place of Bearenger as the boss of Ruin Wood.
The Neave Interactive port of Pac-Man was reskinned and packaged as a new game by many Flash websites. Most of these were amateur jobs, and among those cheap ports existed a reskin of the game on the official 4Kids TV website to promote the 2003 Teenage Mutant Ninja Turtles series, titled Mutant Munchies.
Similarly to Donkey Kong's origins as a Popeye game, Alex Kidd in Miracle World was originally intended as a Dragon Ball game. Alex's creator, Kotaro Hayashida, said in an interview:
"Sega were planning on making a Dragon Ball game... I guess this happened long enough ago that it's okay for me to talk about this! The project began as a Dragon Ball title, not as a direct competitor to Super Mario Bros.
But when we were told we could not use the Dragon Ball licence any more, we were forced to come up with our own ideas instead. For example, when it was Dragon Ball, Goku fought with his Power Pole, but we changed that to a punch attack. It was only after we came up with the plan to restart the project as Alex Kidd in Miracle World that we starting thinking about Mario, and looking for ways in which to differentiate the title from it."
A classic Dragon Ball influence can be observed in the final game, such as Alex's laser bracelet resembling a kamehameha and the use of Janken (Rock, Paper, Scissors) in boss battles, as well as certain character and object designs with resemblance to those from Dragon Ball, and shared influences from the public domain Japanese story Journey to the West.
MK Ultra Girls was a scrapped children's cartoon based on the Mortal Kombat franchise being produced at Warner Bros. Animation around 2020, which would have revolved around aged-down versions of Mortal Kombat characters going to school. The character designs were done by YouTuber Pan-Pizza and the series got very far into production, but was scrapped after a change in leadership at Warner Bros. Animation. Alongside an action figure line, an iOS game based on the engine of Mortal Kombat X Mobile was planned. According to the Redditor who originally leaked the show's existence, NetherRealm "did okay getting these designs in 3D but it's far from done. Progress has halted on the game which is also effecting [sic] the show."
As of 2023, only 4 licensed IP adapted games have been released on Nintendo's retro game digital download services: Teenage Mutant Ninja Turtles for NES on Wii (which was later delisted on January 26, 2012), Transformers: Mystery of Convoy for NES on Wii, Quest for Camelot for Game Boy Color and GoldenEye 007 for N64, the latter two being on Switch.
Additionally, J.J. & Jeff, Punch-Out!! Featuring Mr. Dream, and Super Mario Bros. 2, all reskins of licensed titles, have been available in their license-less formats.
In an Ask the Developer interview by Nintendo, Takashi Tezuka said that the need for a new side-scrolling platformer came out of necessity from him. According to Tezuka, many journalists and players felt that the Super Mario Maker franchise would have ended the need for another 2D Mario game. Tezuka, however, always felt confident that Wonder would be completely different from other side-scrolling Mario installments.
Coming up with brand new ideas was a challenge for Tezuka and his then-small team, and resulted in over 2,000 different ideas on how to make Wonder look fresh and out-of-the-box.
Sonic R has often been criticized for how the playable characters handle like cars instead of athletes - the reason for this is because Sonic R was actually built from a scrapped Formula 1 racing game.
Hard 'n' Heavy was originally conceived as a sequel to The Great Giana Sisters titled Giana 2 - Arthur and Martha in Future World, but was changed due to the threats the developers had received from Nintendo over the previous Giana game. Screenshots and a box art for Giana 2 exist, and show that seemingly only the character of Giana was removed in the transition to Hard 'n' Heavy, but the version of the game with Giana is not known to exist.
Based on evidence from the book Video Game Quest and unused graphics within the game's code, Snoopy's Magic Show was likely originally going to be an original IP, with the title of either Death Ball or Heart Attack.
Yoshi's dialog in Tetris Attack was not rewritten from Lip's dialog in Panel de Pon to account for the dinosaur's more laid back, cheerful personality, resulting in him saying rather stoic fantasy hero lines such as "Together we own our world" or "We can't just be strong, we must be strongest".
Yogi Bear: Great Balloon Blast contains a fully functional unused character in the form of a duo of Dexter and Dee Dee from Dexter's Laboratory, a Hanna-Barbera cartoon that was still airing at the time. It is unknown if this is a remnant of a scrapped Dexter's Laboratory version of Pop'n Pop, much like Dexter's Laboratory: Robot Rampage was for Elevator Action EX, or a scrapped plan to make the game a Hanna-Barbera/Cartoon Network crossover game.
When Elite Software obtained the license to make a video game based on the ThunderCats cartoon, they were unsure if they would be able to complete the game in time for Christmas, and as such outsourced a second ThunderCats game to Paradise Software. Neither game could be finished before the deadline, and as such Elite instead attained the rights to a near-finished game titled Samurai Dawn by FTL Games and released it as ThunderCats: The Lost Eye of Thundera.
Expresso the Ostrich from Donkey Kong Country appears as a cameo in Banjo-Pilot - this seems to be an accidental leftover from the game's cancelled iteration as Diddy Kong Pilot, as Nintendo is not mentioned whatsoever in the copyright info for Banjo-Pilot beyond simply licensing the game for its platforms.
Tails' Skypatrol was originally developed as a licensed Disney game for an unreleased budget handheld system aimed at a younger audience with a focus on educational content - much like Sega's Pico - and was reworked into a Tails game for the Game Gear after the console was scrapped, due to the Game Gear's similar stats to the unreleased hardware. It is not known which Disney character Tails replaced, however a pre-release promotional video shows the Mickey Mouse character Peg-Leg Pete in place of Bearenger as the boss of Ruin Wood.
The Neave Interactive port of Pac-Man was reskinned and packaged as a new game by many Flash websites. Most of these were amateur jobs, and among those cheap ports existed a reskin of the game on the official 4Kids TV website to promote the 2003 Teenage Mutant Ninja Turtles series, titled Mutant Munchies.
MK Ultra Girls was a scrapped children's cartoon based on the Mortal Kombat franchise being produced at Warner Bros. Animation around 2020, which would have revolved around aged-down versions of Mortal Kombat characters going to school. The character designs were done by YouTuber Pan-Pizza and the series got very far into production, but was scrapped after a change in leadership at Warner Bros. Animation. Alongside an action figure line, an iOS game based on the engine of Mortal Kombat X Mobile was planned. According to the Redditor who originally leaked the show's existence, NetherRealm "did okay getting these designs in 3D but it's far from done. Progress has halted on the game which is also effecting [sic] the show."
