The Dragon Quest-esque overworld area, colloquially known as FC World, features a large island on the right-hand side of the map that is not accessible during the normal course of play despite taking up the majority of FC World's land mass. No events or exits are associated with this island, popularly known as FC World C, meaning that hacking the game to place Madotsuki there would prove fruitless.
Despite this, there is evidence that this area was meant to be explorable at one point in development. In the Version 0.09 build (the last one before the "final" Version 0.10 release in 2007), the Dense Woods and Windmill World areas feature the player character from the minigame NASU as an NPC; however, a flag is set to render it invisible (and therefore non-interactable). If the player uses RPG Maker 2003's debugging tools to render the character visible, interacting with it teleports Madotsuki to another unused area in FC World, a small island with four statues on it and an exit at the bottom. Going through this exit takes Madotsuki to FC World C.
While FC World C is still as barren as in other versions of the game, the unused chain of events leading up to it in Version 0.09 indicates that the area was intended to play some kind of role in the final game and that Kikiyama continued to try implementing it late into the game's update history.
In an interview with the developers at Blue Tongue, they mentioned several buildings they wanted to include in this game, but had to drop due to design decisions or memory constraints on home consoles:
•Hotels, which would provide extra accommodation for guests. •Dino-Vet Station, which would have been vital for keeping dinosaurs healthy. •Hunting Platforms, which would let visitors hunt down carnivores in the park from afar.
The Dino-Vet Station can be found in earlier promotional material for Jurassic Park: Operation Genesis and also within its game files. Likewise with the Hunting Platform, which also still has Audio, Ini and even Rig Files within the game.
There are fully functional unused Diggin' Chuck, Bullet Bill, Fishbone, and Spiny enemies in the code of Hummer Team's Super Mario World, as well as sprites for crushers, Lakitu, and Clappin' Chuck without associated coding.
The Saturn release's demo, "Silhouette Mirage: Trial Version", normally ends after level two. However, hidden on the game's disc is an early pre-release build of the retail game, dated 1997-07-16, while the final game has a build date of 1997-07-30. The full game is inaccessible without modifying the data.
Atari 2600's Asteroids has an unused functionality for showing graphics of the spaceship as a life counter instead of the number, much like the arcade version. This was most likely changed for processing power reasons, as only six ships can be displayed at a time.
In the files of the Donkey Kong Adventure expansion, there are unused files for Rambi the Rhino as a party member, including a model; menu icons; and skills. He would have taken up two spaces on the board and been able to charge through any destructible terrain that enemies are using as cover and destroy it instantly. In the final DLC, Rambi would not appear physically in any form, but would have a gun made in his image. Rambi's model looks closer to his appearance in Rare's Donkey Kong games than his appearance in the Paon and Retro Studios Donkey Kong games, a design change that would also be carried over to Super Nintendo World's iteration of the character after Donkey Kong Adventure's release.
The matching card game has an unused card called "MatchPointsSadChef". It does not have any attached graphics. While this card doesn't exist, the game does have a happy chef card, using the chef from Comfy Cakes.
Star Fox Adventures contains a peculiar character named the WarpStone, a living stone creature that has the ability to warp users to the top of Ice Mountain and also Krazoa Palace, where Fox will need to deposit all of the six Krazoa Spirits he acquired through partaking through the Krazoa's trials in order to save Krystal, who is imprisoned at the top of the Palace. Underneath the WarpStone also lays the Game Well Maze, where Fox can deposit any of the Cheat Tokens he's collected from Scarab Wells hidden in the map throughout his Adventures to unlock extra features and also cryptic messages.
In Dinosaur Planet, the WarpStone was originally meant to be two different characters, the SwapStone twins known as Rocky and Rubble. Hence their name, their original purpose was to let the player be able to switch back and forth between Sabre and Krystal's adventures. Sabre would utilize Rocky in an area called SwapStone Hollow, while Krystal would utilize Rubble in her equivalent, SwapStone Circle (which is also where the LightFoot Village was situated). Both characters would also retain the ability to warp their respective character to Warlock Mountain (the predecessor to SFA's Krazoa Palace) where the characters could similarly deposit the Krazoa spirits they acquired from the Krazoa shrines. Underneath the SwapStones was the only in-game store where Sabre and Krystal could purchase items, maps, etc. Curiously, their bio claims that they were created during the age of the Krazoa, by being mined from the magic rock of Warlock Mountain, and that they assisted in the creation of the Force Point Temples and the Krazoa shrines.
As Krystal's playable co-protagonist role was scrapped in SFA outside of the prologue, the SwapStones were merged into one character, the WarpStone, and SwapStone Hollow was renamed to ThornTail Hollow. SwapStone Circle would be effectively removed, but the LightFoot Village segment was heavily expanded into its own distinct area. In place of being able to swap to Krystal, Fox could be teleported back to the top of Ice Mountain where he could replay the jet bike race against the SharpClaw. While early design documents, leftover data from the E3 2002 kiosk build, and as well as an unused audio file found within the retail release of SFA indicate that the store was still planned to be located underneath the WarpStone, in the final game it was relocated to the middle of ThornTail Hollow as its own distinct establishment, the ThornTail Store, and the alformentioned Game Well Maze took its original intended spot.
Diving in to the game files, it seems Rare had also intended on letting the WarpStone teleport Fox over to additional areas such as Cape Claw, Moon Mountain Pass, and the Force Point Temples, but this was scrapped and currently, the WarpStone can only warp you to Ice Mountain and Krazoa Palace.
The Noise, Pepperman, and The Vigilante were all planned to be playable at some point - Vigilante and Noise were both intended to be regular playable characters, while Pepperman was intended as a one-level only character on Refrigerator-Refrigerador-Freezerator, much like Gustavo & Brick. All 3 of them have code and animations left over in the game, of varying compatability. The Noise would later be re-added in a future update due to all of his animations being completed.
In 2013, a Kingdom Hearts online mobile game was in development that never saw the light of day. It was to be called "Kingdom Hearts: Fragmented Keys". The game was rumored to feature customizable avatar characters (like Union Cross). It would also have been in 3D instead of Union cross' 2D art style. Most interesting and exciting of all though (gathered from concept art no less) was the Disney world list as the game would feature returning worlds like: Agrabah, Wonderland, a Lilo & Stitch Hawaii world, Space Paranoids/The Grid, London/Neverland, and Dwarf Woodlands. It also included worlds that didn't appear in the series yet but would appear in later games like Union Cross and Kingdom Hearts III, such as: Arendell (Frozen), Kingdom of Corona (Tangled), and Niceland/Game Central Station (Wreck-It Ralph). Finally, and most shockingly, a world based on the Star Wars franchise, although this world's chronology is unknown as concept art show different conflicting eras, such as an image of characters Anakin, Obi-wan, Padme, and Master Yoda in their exact looks from Star Wars: The Clone Wars movie and series in a separatist gunship's hanger as well as a planet that looks similar to Tatooine and an anachronistic Death Star power station room. It is unknown why this game was cancelled.
If one moves Hank's Microsoft Agent actor file into the the main Microsoft Bob application, he can be used as a main Bob assistant, complete with his own character bio, suggesting that he was meant to be part of the wider Microsoft Bob program. Some of his text is generic placeholders and he does not have a background (instead using a close-up of what appears to be his knee or elbow).
Pregnancy was supposed to be a condition in Theme Hospital. It is somewhat finished and can be restored with modding, but lacks graphics and is referred to as a "disease".
In the Game Boy Advance version of Harry Potter and the Prisoner of Azkaban, there is an unused minigame that is just a clone of Tapper, with Pumpkin Juice in place of beer.
Inside the code for the SNES version of Daze Before Christmas are a set of mostly Christmas-related quotes and messages:
Any dramatic game the producers want us to take seriously as a representation of contemporary reality cannot be taken seriously as a representation of anything -- except a game to be ignored by anyone capable of sitting upright in a chair and chewing gum simultaneously. -- Richard Schickel (slightly modified)
... Now you're ready for the actual shopping. Your goal should be to get it over with as quickly as possible, because the longer you stay in the mall, the longer your children will have to listen to holiday songs on the mall public-address system, and many of these songs can damage children emotionally. For example: "Frosty the Snowman" is about a snowman who befriends some children, plays with them until they learn to love him, then melts. And "Rudolph the Red-Nosed Reindeer" is about a young reindeer who, because of a physical deformity, is treated as an outcast by the other reindeer. Then along comes good, old Santa. Does he ignore the deformity? Does he look past Rudolph's nose and respect Rudolph for the sensitive reindeer he is underneath? No. Santa asks Rudolph to guide his sleigh, as if Rudolph were nothing more than some kind of headlight with legs and a tail. So unless you want your children exposed to this kind of insensitivity, you should shop quickly. -- Dave Barry, "Christmas Shopping: A Survivor's Guide"
I stopped believing in Santa Claus when I was six. Mother took me to see him in a department store and he asked for my autograph. -- Shirley Temple
Courage the Cowardly Dog: Creep TV has secret codes and maps that went undiscovered until 20 years after its release due to a glitch making them inaccessible. The codes include the "daScore" code, which shows a counter of how many ghosts you've zapped, and the "mirage" code, which expands the game map infinitely and allows access to the secret maps. On one of these maps, you can acquire a pair of glasses as an unused item, and another map containing an oasis in the Middle of Nowhere that also has a sign simply reading Eustace's catchphrase, "STUPID DOG!". However, if you use the glasses to read the sign, it will instead say "Wee...amazing! You found it! GOOD DOG!"
Q*Bert was originally able to shoot projectiles out of his nose, but this was scrapped in the final game. Co-creator Jeff Lee has said that, while he's unsure if this change enhanced the gameplay or not, he likes how the lack of offensive capabilities gives the character the personality of a "sympathetic plucky noser" who survives "by his wits and dexterity", particularly with the hindsight of how violent video games would become in the decades since.
The Dragon Quest-esque overworld area, colloquially known as FC World, features a large island on the right-hand side of the map that is not accessible during the normal course of play despite taking up the majority of FC World's land mass. No events or exits are associated with this island, popularly known as FC World C, meaning that hacking the game to place Madotsuki there would prove fruitless.
In an interview with the developers at Blue Tongue, they mentioned several buildings they wanted to include in this game, but had to drop due to design decisions or memory constraints on home consoles:
Atari 2600's Asteroids has an unused functionality for showing graphics of the spaceship as a life counter instead of the number, much like the arcade version. This was most likely changed for processing power reasons, as only six ships can be displayed at a time.
In the files of the Donkey Kong Adventure expansion, there are unused files for Rambi the Rhino as a party member, including a model; menu icons; and skills. He would have taken up two spaces on the board and been able to charge through any destructible terrain that enemies are using as cover and destroy it instantly. In the final DLC, Rambi would not appear physically in any form, but would have a gun made in his image. Rambi's model looks closer to his appearance in Rare's Donkey Kong games than his appearance in the Paon and Retro Studios Donkey Kong games, a design change that would also be carried over to Super Nintendo World's iteration of the character after Donkey Kong Adventure's release.
Star Fox Adventures contains a peculiar character named the WarpStone, a living stone creature that has the ability to warp users to the top of Ice Mountain and also Krazoa Palace, where Fox will need to deposit all of the six Krazoa Spirits he acquired through partaking through the Krazoa's trials in order to save Krystal, who is imprisoned at the top of the Palace. Underneath the WarpStone also lays the Game Well Maze, where Fox can deposit any of the Cheat Tokens he's collected from Scarab Wells hidden in the map throughout his Adventures to unlock extra features and also cryptic messages. 
In 2013, a Kingdom Hearts online mobile game was in development that never saw the light of day. It was to be called "Kingdom Hearts: Fragmented Keys". The game was rumored to feature customizable avatar characters (like Union Cross). It would also have been in 3D instead of Union cross' 2D art style. Most interesting and exciting of all though (gathered from concept art no less) was the Disney world list as the game would feature returning worlds like: Agrabah, Wonderland, a Lilo & Stitch Hawaii world, Space Paranoids/The Grid, London/Neverland, and Dwarf Woodlands. It also included worlds that didn't appear in the series yet but would appear in later games like Union Cross and Kingdom Hearts III, such as: Arendell (Frozen), Kingdom of Corona (Tangled), and Niceland/Game Central Station (Wreck-It Ralph). Finally, and most shockingly, a world based on the Star Wars franchise, although this world's chronology is unknown as concept art show different conflicting eras, such as an image of characters Anakin, Obi-wan, Padme, and Master Yoda in their exact looks from Star Wars: The Clone Wars movie and series in a separatist gunship's hanger as well as a planet that looks similar to Tatooine and an anachronistic Death Star power station room. It is unknown why this game was cancelled.
If one moves Hank's Microsoft Agent actor file into the the main Microsoft Bob application, he can be used as a main Bob assistant, complete with his own character bio, suggesting that he was meant to be part of the wider Microsoft Bob program. Some of his text is generic placeholders and he does not have a background (instead using a close-up of what appears to be his knee or elbow).
In the Game Boy Advance version of Harry Potter and the Prisoner of Azkaban, there is an unused minigame that is just a clone of Tapper, with Pumpkin Juice in place of beer.
