Both Baldur's Gate and its sequel had some incomplete content in it. Fans scouring through the source code have, with some help from the original developers, created mods which restores some of this content, called Unfinished Business. In the original game:
In Tales of the Sword Coast, there was an entire level of Ice Island that was cut for having damaged files. BG1 Unfinished Business restores this second-level from the files still on-disc.
Several cut encounters still have files on-disc, including an additional Elminster conversation outside the Friendly Arm Inn, dialogue between Kivan and Tazok at the Bandit Camp, and an extra encounter with Branwen and Tranzig.
Safana originally had a different innate ability - instead of Charm Animal, she had Flirt, which could be used to accomplish the same effect on human men.
Several cut weapons, including a unique club (The 'Root' of the Problem) and an alternate +2 Studded Leather Armor set.
In Shadows of Amn:
Minsc originally had a sidequest of his own, which was removed from II before its release (although several unused lines remain). In his quest, Minsc loses Boo (his "space hamster") when you travel from one area to another, and he asks the player character to help him find his companion. The player must then follow a series of clues by interrogating several residents in Athkatla, and eventually tracks Boo down to a wealthy member of the city who bought the creature. If the player chooses not to help, Minsc suffers several penalties, and permanently leaves the party after a set period of time. If the quest is completed, Minsc gets a THACO and chance-to-hit bonus. Unfinished Business restores the bulk of the quest, with some material being changed to make it more coherent.
Two Ranger character kits (the Justifier and Feralan), two character portraits (Yoshimo and Anomen, who had their pictures changed for the final game) and several items were deleted, but all have their original files still on-disc.
Valygar originally had several encounters with Suna Seni (who Irenicus had also put under a geas) in Athkatla, which gives more information about their past relationship. The encounters were cut from the game, but the text files still exist on-disc.
Bodhi was originally intended to "hunt" the player and their party when they were trapped in the trials underneath Spellhold, but this was cut in an effort to tone down the overall difficulty level of the game. In addition, another gameplay encounter between the Shadow Thieves and Bodhi was also cut.
Artemis Entreri was intended to appear in Bodhi's Lair (in Chapter Six) if you enlisted Drizzt and his group to help during the raid. This was cut presumably because Drizzt and Artemis were at odds at that point in the narrative.
In Throne of Bhaal, Demogorgon was originally intended to be much tougher than the version seen in the final product. David Gaider's Ascension mod restores the original difficulty of the boss fight and makes him much tougher. Several Bhaalspawn powers (which were acquired after the various Trials) were also cut from the game pre-release for being too confusing - Ascension also restores the original concept.
Sarevok in ToB also had a cut conversation where he expresses remorse for the deaths of Tamoko and Yoshimo to the player character. This was related to his chance to change alignment.
A large amount of material was cut from the original Deus Ex prior to its release. Using console commands, it's possible to access a selection of cut content:
Originally, the player could choose to stay with UNATCO instead of transmitting the NSF emergency signal. Conversations can be accessed that have JC telling Paul that UNATCO isn't perfect (but he'll stay with them anyway), and, later on, the troops on the superfreighter being able to talk casually with Denton. It's believed the alternate plotline was removed either because it was much shorter (content-wise) than the NSF plotline, or there wasn't enough time to finish it.
You can use a console command to summon Ford Schick (who normally disappears after saving him) in Smuggler's hideout, where he has a full set of lines thanking you and offering augmentation upgrades.
Technically Schick wasn't Dummied Out, but rather fails to show up due to a bug: the flag that marks him as being rescued is not set to persist past the next mission.
There was an entire level planned at the White House, where JC would supposedly visit the President and his wife and get advice. It was cut because the designers thought it would be boring, but various elements can be summoned through the console.
Amusingly, the President's daughter is reused in the Hong Kong level, repurposed as a prostitute.
At one point in the game's development, there was a plotline where JC would discover that Maggie Chow was married to Paul Denton. By clipping outside of the Wan Chai Market, you can find a Red Arrow guard that tells you about this plot point, and gives you tips about the people in the area. It's unknown if this was actually a planned plot twist or just Chow trying to throw you off her trail.
There are all sorts of deleted items and NPC's that can be found in the gamecode, including an alternate Chinese security bot.
The fact that, when activating the console cheats, the user needs to specify JC's sex (along with the gender-neutral language refering to the Dentons used in the opening cutscene) suggests that the developers were planning to allow the player to choose which gender the Player Character could be. This was a feature later fully implimented in Deus Ex: Invisible War.
An answering machine in Paul's apartment that would have hinted towards his loyalties to the NSF.
A VOIP conversation in the airfield level between Juan and Tracer, with the latter urging the former to kill the player.
In Deus Ex: Human Revolution, applying a fanmade patch to the game would allow the player to access a special debug menu that would allow them to play the E3/Gamescom variants of the final levels.
Deus Ex The Fall, texture files hinting towards a New York City level, a Lower Hengsha level, and an Australia level. Since this game has been pitched to be episodic, it is unknown at the time of writing if it is cut content, or just textures in place for future installments. An album can be seen here.
The Elder Scrolls
In general, many of the later entries have several dummied out and test areas that are accessible through console commands. These range from empty rooms to unused dungeons to areas with every item in the game. Several of these areas can get very... strange, such as a room with an NPC that grows when you try to talk to him, or another that turns into a staff when killed.
In Daggerfall it's widely believed that the many outfits you can dress in were going to be used for the purpose of using different ones depending on the NPC to interact with them, but nothing comes of it in the release.
Daggerfall also contains some unused dialogue files that indicate you were supposed to be able to sleep with the prostitutes found in many of the inns. You can't.
The dialogue files also have little bits of doggerel verse that were supposed to have been pieced together by NPC minstrels so that you would be able to hear the fame of your deeds spread.
Various stores which were used as fronts for the Thieves Guild have a sign that looks like the store was to sell furniture. Thanks mostly to the incredible work by the Andyfall mod, the remnants of code used for a furniture purchasing system that was never completely implemented was uncovered.
Containers are broken in the game. Originally the player was intended to be able to casually store furniture on shelves and in chests, but that feature had to be removed due to problems.
The Earth Wall spell in Arena was cut because of the technical difficulties of implementing user-made dungeon paths between the different dungeon sections in a 3D environment (Arena was a 2.5D game).
A data file exists in Daggerfall which consists entirely of various rhyming lines. The developers have revealed that originally, there was going to be a troubador who would compose poetry of your exploits.
The game has much, much more extensive elevation data than what actually is used in-game. The land data was dummied out by some code keeping the game from reading it (although, this being Daggerfall, bugs can cause it be read), while the sea data apparently is used... it's just that outdoors underwater swimming was dummied out, so you can't actually see it.
The Order of the Lamp (a knightly order dedicated to the Mages' Guild) was intended to be joinable (not only were there developer comments on it during the beta, but talking to local Order heads gives a dialogue using the standard model for joinable factions, explaining purpose and what they look for in recruits). It isn't.
There is an alchemy ingredient called "bloat," which can be purchased from merchants or found in random crates. Where bloat comes from is never explained in-game - but the level editor reveals an unused "bloat spore" plant that was supposed to produce them, but was never placed in-game. Several mods out there deal with this, ranging from placing them in several swampy areas to working them into a House Telvanni quest line as being in a bloat mine.
There is a fountain in Morrowind called the Pool of Forgetfulness. Players have frustratedly tried to get it to do something, but it apparently does nothing. Perhaps the developers simply forgot about it?
To defeat the Big Bad, players need two special weapons called Sunder and Keening, which are being guarded by the Big Bad's higher-ranked minions. The data files of the game reveal a phony look-alike of Sunder, and a voice file for the Big Bad taunting you when you try to kill him with it. These never got included in-game.
The idea was borrowed by a large fan mod that opens up a series of quests for the Sixth House, treating it like a guild, and building an alternate main quest. One new weapon is named as a prototype of the Keening.
"The Wings of the Queen of Bats", Morrowind's Infinity Plus One Axe, isn't actually in the game, but can be obtained through cheat codes or modding the game.
Morrowind also has a version of Azura's Star that can be used as a shuriken, but the final game replaces it with a Soul Gem.
There are several quests, in various states of completion, that got blocked off from being gettable. One of them can partly break the Imperial Legion questline (you can't get the quest... but the dialogue for completing is in enough that you can get the completion dialogue in the right circumstances. Unfortunately, this makes the game think you are on that quest and so block off further quests from that quest-giver).
Oblivion and other games in The Elder Scrolls series have some quests which were never implemented (for example you can pick up the topic "Are you looking for couriers" in the Imperial Marketplace but none of the NPC have it as an option).
There are several of these quests that are hinted to but never programed, including one involving a cave (in the game, but there's nothing there) and a women named the Red Queen (not in the game, but mentioned by NPCs), and one involving rescuing a self-proclaimed half-ogre from being eaten when he tries to contact his relatives (the half-ogre is in the game, but he doesn't serve any purpose). There's also the infamous city of Sutch, mentioned and used for early development videos, but not in the game due to time constraints.
Another involves the NPC Branwen, who is perpetually sparring with her Argonian partner Saliith outside in the Arena district. There's a note on the floor inside the Bloodworks near Owyn that indicates he is her father and she wants to become Champion in order to impress him, but there's never any further implementation of the quest. Like many others, some enterprising modder has finished it.
Oblivion also contains some item models that for some reason were never attached to their respective items. E.g. there's a unique mesh and texture for cyrodiilic brandy in the game data, but the game just uses a generic potion bottle for the drink instead.
Also, there's a reason why you can't wear anything above the waist. Why? Because the female models have bare breasts with nipples — as revealed by an Oblivion mod that lets you take off your top clothes. (As with "Hot Coffee," this resulted in the ESRB altering the game's rating — as well as the ESRB having seen a pre-release build that didn't have some of the more intense violence, such as the mutilated corpses.)
A caveat rendered ridiculous by the fact that, thanks to a large and dedicated modding community, there is now a hirez model for any possible nude female body type (and a couple of male ones, with or without erect member), from flat chested through ridiculously enormous. Almost all have some sort of Stripperiffic clothing support as well.
A platform specific dummied out, the Xbox 360 version of Oblivion is missing a piece of music called Auriel's Ascension. The music is part of the game's "Explore" package, meaning it would play while you are out exploring the Cyrodiil countryside, however it only plays in the PC and PS3 versions of the game. The track is present however in all Game of the Year versions of the game.
While predecessor Morrowind has the Levitation spell that allows you to fly around at will, Oblivion doesn't. The spell was cut from the game because of the ways cities are treated; Morrowind had them as permanent part of the game world, but Oblivion confines them to their own maps, accessible only through the doors, and the player isn't supposed to go outside in other ways. This is easily visible by using a cheat to fly outside the walls; the outer world is a sparse version of the original, with no content whatsoever aside from a few inert buildings.
Children killing was hinted to had been considered for inclusion, as there were death sounds recorded for children. Mods restore this concept.
There were originally plans for an arena in Windhelm, which would feature various NPC's, a couple of quests and the opportunity to take part in gladiatorial matches. The area appears to have been cut fairly late in development, because numerous assets are still on the game disc, including NPC spectators, a female warrior who would give you a quest to kill Alain Dufont (who is a target of the Dark Brotherhood in the finished game), and two unused maps.
Several unused quests, including one where the player could kill the Jarl of Solitude, Elisif, to appease Boethiah the Daedric Prince, several from the College of Winterhold (one of which had the player track down a rogue wizard), several miscellaneous quests and more. Some of these are restored by the aptly-named Cutting Room Floor mod.
The Civil War had a lot of unused content, and was intended to be much more extensive than it was, with elements like sieges on Riften and Markarth, the ability to attack/defend any capital, encouraging soldiers to defect, recruiting giants, a resource system that was based on how many mines/settlements the various factions had captured and much more. Several mods (like Civil War Overhaul) restore the bulk of the deleted content. The fact that mods are specifically mentioned in the game files for the CW coding scripts lends credence to the suggestion that the expanded storyline was cut due to time constraints and left on the disc for enterprising modders to finish.
Using the Fallout 3 GECK Editor, you can find a abundance of strange items and NPCs with no model. There was going to be a better Tesla Armor that involved something called "Robo-Thor". Who was O'Grady, and why does he have his Peacemaker? Was Three Dog supposed to wield Law Dog? And was whatever the "Spinebreaker" thing that was explicitly used to scare the player in Vault 87 related to that Failed FEV Subject, and where does it "spawn the Super Mutant and start him running"?
These items can also be discovered and obtained by PC users without the GECK by typing "coc testqaitems" in the console. This takes the player to a room designed to test various items. Several of the dummied out items appear here as well.
In a reversal of the usual removal of features for Western versions, the Japanese version has the evil resolution of the Megaton bomb quest removed (since it involves detonating a nuclear bomb and destroying a town. Japan is a little sensitive about that kind of stuff.) by removing the NPC that would trigger that part of the quest. The only thing you can do is disarm the bomb (the good resolution). As a result, the Tenpenny Tower suite and destroyed Megaton are unaccessible in the Japanese version of the game.
The Loading Yard at Mama Dolce's has a gate that "Requires a Key", but can't be unlocked and leads nowhere. Possibly intended for DLC that was never made, or just to psych the player.
The atrium for Vault 87 is dummied out with a "Requires Key" door that can only be opened via console command. The characteristic inner vault door leads into a blank void, rather than an entry tunnel (which would be collapsed anyways).
This door does have a purpose, however, since it is the point where the Enclave enter during the cutscene when they capture you.
Another room that is present but inaccessible without console hacking or glitching is located in Vault 92 Sound Testing, blocked by a jammed door. Beyond this is a door leading to the Overseer's emergency tunnel, which can't be accessed from the Office side but may have been intended to be.
Megaton also has the Abandoned House, an untextured prototype version of the house you get for disarming the bomb.
The Winterized T-51b Power Armor from Operation Anchorage was originally meant to be degradable like the standard T-51b from the core game, which would mean it couldn't be fully repaired, reducing its usefulness. The developers apparently realized this and scrapped this version in favor of the indestructible simulation version. The destructible version still remains in the code.
In-game text prompts indicate that the armor in Fort Constantine was originally going to be the Medic Power Armor (which is found in the Old Olney Sewers in the final game) rather than the T-51b.
In Broken Steel, a "beta" version of the Tesla Cannon can be found hidden in the Rockland Satellite Relay Station cell.
One of the burned-out houses in Springvale has a key-locked cellar door. In the base game it is inaccessable, but in the Broken Steel DLC, it is the location of the Holy Light Monastery. Ditto the Hank's Electrical Supply building. Similarly, in Vegas, there are four locations in the vanilla game's Wasteland with inaccessable passageways or inactive objects, but which become the entry points to the DLC areas once those are installed.
The sub-basement of the Tops Casino is not normally accessible by the player, but if you have Benny accompany you to the Presidential Suite and kill him before he escapes, a glitch causes the elevator to remain unlocked, allowing you to access it and a sealed-off area of Vault 21. Something may have been planned for this area.
Unusable Welding Guns can be found in various locations; they were likely meant to have crafting functions that were never implemented.
There is a dummied-out armored version of the Vault 21 jumpsuit, which is in fact the same version worn by the Courier in the ending slideshow.
New Vegas includes a number of unused weapons and enemies, such as a non-unique version of the "This Machine" weapon and a giant fire gecko with an editor ID labeling it "Gojira". The former was likely cut for time and is re-added in the Gun Runner's Arsenal DLC, while the latter was just made for fun and requires mods such as New Vegas Uncut, which spawns it once the other legendary creatures in the game are dead.
Text dumps of the original Final Fantasy reveal a line that one of the Sages was meant to deliver late in the game: "In the Temple of FIENDS are the remaining SKY WARRIORS. They fought the FIENDS and are now bats!" Its absence is more likely an accident than a deliberate choice, since the bats will tell you their story anyway (and FF1 is famous for its sloppy coding, which made whole gameplay components useless). The line is back in remakes of the game.
Accidental example: The Angel Ring in Final Fantasy I: Dawn of Souls is supposed to be found in a treasure chest on the 33rd basement of the Whisperwind Cove, a Bonus Dungeon with 40 floors, each floor being a randomly selected one out of a set of pre-made floors. Unfortunately, the only floor that gives you the chance to collect the ring (since it's the only one that has enough treasure chests in it) is never selected to be the 33rd floor.
The first US release of Final Fantasy IV had many items dummied out. Some of them were inexplicably restored when it was ported back to Japan as Easytype.
Also, a few spells were removed, those being the White Magic spells Protect, Shell, and Dispel, and one of Rydia's summons, Cockatrice. These spells were actually left out in the aforementioned Easytype version as well, but could still be accessed by using certain pieces of equipment (see below).
Another element that was removed was the ability to use certain pieces of equipment to cast magic. This feature was restored when it was ported back to Japan as the Easytype version, however. Interestingly, in the SNES version, the PROGRAMMING was still there. If one used a Game Genie (or other cheat device), the commands could be re-enabled, and you could also buy and use the removed items, even the Soma Drop or Gold and Silver Apples. They would simply be called "Dummy" in the inventory...you just had to remember which was which.
The DS port also, frustratingly, had the vocal version of "Theme of Love" dummied out of international releases for no apparent reason and now the credits, where the song was supposed to play, have generic background music in them instead. Rumor holds that the vocalist for the song's manager hadn't signed away the international release rights to the song, wanting to keep it Japan only. Squeenix should have played the instrumental version of the "Theme of Love" at least.
In Final Fantasy IV: The After Yearsall of the items from the GBA version of Final Fantasy IV are included in the code; plus some "Uber" Debug equipment named after the programmers that makes you invincible. You're not going to see these without cheating.
There are also dummied-out commands. Some of them were available in the GBA version of the original game (Brace, Cry, Dark Wave, etc.), but some are upgrades of existing commands that are completely unavailable in either game through normal methods (Double Throw, Omni (attacks all targets at once), etc.), and most interestingly, there's also a dummied-out command for Blue Magic. Common Fanon theory is that Blue Magic was supposed to be on Harley but was removed for some reason.
Famously, the Czar/Kaiser Dragon in Final Fantasy VI. The developers later reused its name for a boss in Super Mario RPG and in its original game it was apparently intended to be a Bonus Boss, as this was the case when it was finally put in the game in the GBA remake - although it did have an associated speech even in the SNES/SFC game that suggested it was supposed to be some manner of uber-enemy.
Another example would be the Colossus. Unlike the Czar Dragon, he had a complete battle script and for some odd reason was programmed to attack wild kid Gau if he was in the party.
Famously, the Honey Bee Inn in Final Fantasy VII has many dummied rooms, characters, and script.
Final Fantasy VIII has an entire mini-game mode for the Pocket Station, which never made it out of Japan. Said mode is still referenced in the English release and manual, probably because the decision not to release the hardware hadn't been made yet. It is (or at least was... the game is now over 10 years old) possible to play it with an imported Pocket Station from Japan. The mini-game could be used to get many useful items, and of course, 100% Completion.
The PC version of Final Fantasy VIII has this mini-game as a separate program which can be left running on the desktop while you play (or indeed, while you aren't playing). It still connects to the game like the original Pocket Station version did and can provide very helpful items early on.
Because this version was hastily thrown together, it's entirely possible to make a back-up of the minigame's save file before you import it, import the files, and then overwrite the updated save file with the backup. Repeat infinitely or until you have every item in the entire game, making it a serious Game Breaker.
Originally, Selphie was supposed to have two more Limit Break spells which apparently were never programmed in. These spells were Percent which cuts all enemies by 93.75% of their current HP and Catastrophe which is more powerful than the ultimate spell, Apocalypse. They can be accessed with a Gameshark.
Digging around in the code of Final Fantasy XIII-2 reveals a model of young Hope that was not used in the game, combat data and a Chocobo-riding animation for older Hope, models of a few Fal'Cie, and the l'Cie crystals of Serah and Cid Raines.
Taris had several areas that were cut prior to release, including an additional level of the Black Vulkar base (where you would have to masquerade as a Vulkar to get into the garage), part of the Gamorrean stronghold in the Undercity and access to the swoop platform before and after the required story race. Mods restore access to these areas.
Normally, an NPC you encounter on Tatooine (Sharina) disappears after you complete a quest for her (helping her to sell an item to pay for passage off the planet and settle elsewhere with her family). However, she was originally intended to appear on Dantooine, where she would thank the player for helping her. It was likely scrapped because Dantooine is carpet-bombed by Darth Malak just before the endgame, rendering her quest a waste of time. This additional appearance was restored through mods.
Normally, Bastila won't venture out of the Ebon Hawk on Korriban because she is concerned that the Sith will recognize her. However, a mod exists that allows you to take her anyway, where she has a full set of dialogue reacting to various events and training challenges in amusing ways.
There are several other cut areas, including an incomplete Rakatan ruin on Tatooine (with a Sarlacc pit!), a Czerka regional HQ on Korriban (which was reused in the massive content mod Brotherhood of Shadow: Solomon's Revenge) and a third level of the Kashyyyk Shadowlands. There's even an entire world, Sleheyron, that was cut prior to release and has very little information to go off of, with modders working on long-term projects to build the area. Here are some mods that restore or use dummied out content as a base.
Three additional BIK movies (one with the Ebon Hawk outrunning enemy fighters while leaving Taris, and two where it approaches the Star Forge) were cut prior to release, but can be reintegrated with mods.
An alternate ending for the Dark Side female PC which would have allowed her to take the Last-Second Chance offered by Carth was lost to this.
Juhani, one of your party members, is rumored to have been removed from the game and then put back at the last minute. The rumor exists partly because she is a character with the Gay Option, but more because poring through the data files reveals a lot of dialogue that got left out. This includes her observations about the various planets you visit, a few other comments, and her revealing to the player her deep distrust of a Mandalorian.
An entire planet, M4-78 (which is solely inhabited by droids), was cut by Obsidian in the rush to get the game out the door and was finally restored by modders several years later via the M4-78 Enhancement Project. It has a full set of quests to re-activate the planet, plenty of NPC's and unique upgrades for droid party members. Not only that, but completing the quests and choosing to ship its resources to a station nets you more NPC support during one of the final battles.
Several rooms on the Ravager are inaccessible, but using no-clip to enter them show that many of the rooms are complete with textures, indicating that they were to be entered at one point in development.
Due to being rushed to publication, the game had a lot of content dummied out, including most of the final mission on Malachor V. The "Sith Lords Fan Restoration Project" has modded the material back in. There's also this Let's Play, which hacks the game and takes a look at a ton of the cut content. It even has an actual ending.
A lot of unused lines, game mechanics and plotlines were left out of the Mass Effect series.
In general, elements that appeared in later games could be found in unfinished/beta formats in earlier installments. The Cerberus logo and squadmate portraits appeared in the image files for ME1 (despite never appearing anywhere until the sequel), and ME2 has a text description for a robot dog (called Sparky) that could be purchased and roam the Normandy - a concept that wasn't realized until ME3.
Four weapon manufacturers (Batarian State Arms, Cerberus Skunkworks, Hahne-Kedar Shadow Works and Jormangund Technology) were cut prior to the game's release, but all of their weapons and armor can be summoned through console commands in-game.
Notably, there is a piece of cut dialogue that states that both Ashley and Kaidan could be rescued during the Virmire mission, with both commenting on a "stunt" Shepard pulled to rescue both of them. The concept was removed from the game because Bioware thought it would make writing future plots more difficult, as no one would bother to save only one person instead of both.
A cut piece of dialogue has Mark Meer state that he (as Shepard) and Liara are "both women", but it's unknown what context it could be used in.
It was possible to go for any of the recruitment missions at any time after you received the Normandy SR2 (including Legion, who only shows up in the final game on the mission just before the endgame begins). This was changed when the game was split onto two discs for the Xbox 360.
The decision to make all weapons solely clip-based came late in development, as an unlimited-ammo option (like the first game) was programmed in, and can be reactivated by modifying the game's Coalesced file. Early video previews showed more involved gun mechanics; guns had ejectable thermal clips as a "need More Dakka right this second" option. Specialized ammunition was shown to be a consumable resource instead of a passive ability and as such could be turned on or off at will.
Same-sex romance options were written and fully voice-acted for Kaidan Alenko and Ashley Williams, but were left out of the original game. In the sequel, there exists coding that suggests Tali and Thane could be romanced by both male and female Shepard.
The Lair of the Shadow Broker DLC has several cutdialoguesequences that assume a female Shepard romanced Jack, Miranda or Tali. These suggest that the FemShep romances were planned, but scrapped very late in production.
Harbinger has unused taunts and a longer ending speech that would have played as Shepard and his/her team flee the Collector base, where he comments that many more Reapers will be coming soon. It is believed that Shepard's dialogue in the worst possible ending (where he/she falls from the Normandy) references this deleted footage.
There are text logs for several e-mails never used in the game still on-disc, including one from Captain Kirrahe if he survived, the Illusive Man congratulating you on finding the IFF, and an unused mission regarding the retrieval of probes left on a planet.
At one point, Mordin would have had the option to create a biotic field (for the "Long Walk" portion of the suicide mission). Several voice files were recorded with Mordin telling the team he can create a biotic field, and his reactions during that section of the mission. It was also discovered that there was an option to upgrade any squadmate's abilities to become the Tech/Fire Team Leader/Biotic Specialist as they have success lines.
In an earlier version, it was possible to complete Tali's loyalty mission without ever seeing the body of her father, Rael'Zorah, and have others comment on the fact that he couldn't be found.
Deleted voice files indicate that there would have been a confrontation scene between Mordin and Grunt. This was removed to focus on confrontations between possible love interests (Tali, Miranda and Jack) and vital squadmates for the loyalty mission since it is very easy to be without them.
The DLC characters (Kasumi and Zaeed) had changed personal missions in development (as evidenced by text files found on the disc). Kasumi's mission originally involved going after a company called Nava Corporation that was going to unleash a series of bio-viruses into the Alliance, while Zaeed's involved going after a fellow bounty hunter who's "gone corporate", then faking his own death to throw other bounty hunters.
Due to a Event Flag bug in the previous title that leads both mutually exclusive Charm and Intimidate flags to be checked, and a failsafe feature in the import code, the Conrad Verner sidequest on Ilium would always be treated as if Shepard used the renegade dialogue options in the previous game, effectively making the paragon opening this. It even gets referenced in Mass Effect 3 when Conrad apologizes for saying you pointed a gun in his face if you really didn't.
In Mass Effect 3, there are several files on-disc that contain deleted or removed material from the game:
A (text) conversation between Ashley and Shepard onboard the Normandy, where she asks if Shepard remembers what being dead was like and if there's an afterlife. It was likely removed either due to overt religious tones, or because, despite the reputation, Shepard never reallydied, due to his/her brain being 100% intact.
Ken and Gabby were originally meant to be recruited not through a Spectre terminal, but in an actual conversation/dialogue scene in the Purgatory Bar. The scene got far enough long that the lines and animations were recorded for it, but the camera work was never finished. A mod restores this sequence.
Likewise, Zaeed was originally intended to have a full conversation with Shepard at the Citadel Refugee Area, explaining the history of the Blue Suns, what he did in between games and his involvement in the war. It also never had its camera work completed, but was restored through mods.
Ashley has a lotofunused / bugged dialogue, including multiple lines related to her romance arc and love scene near the end of the game, which put her much closer to her ME1 characterization. Likely cut for reasons of Character Development.
Lots of deleted audio files from various characters participating in the Priority: Earth mission, including, Grunt (who has a rallying cry about Earth and Tuchanka), Jack (who tells her students she's proud of them before they go into battle), Jacob (who says "This is my planet, assholes!") and Zaeed (who yells, "Burn, you son of a bitch!" while likely using his Inferno Grenades on a pack of Husks.)
The original version of the Conduit Run, where Shepard's teammates are injured and (depending on the player's EMS) either hobble away from the battlefield or are vaporized by Harbinger's beam. The concept was restored, albeit in a different fashion, in the Extended Cut DLC.
Additional Joker dialogue during the push towards the Conduit. Joker gets several lines, including "I'm late to the party, but the girls are coming home with me!" and "That was for Cortez!"
An audio file of an extended version of Anderson's final speech with Shepard, where Anderson talks about possibly raising a family after the battle for Earth. The scene was apparently removed by the development team for dragging too long, even though most people seem to agree that the scene would have worked much better with the additional dialogue.
Due to coding problems with the Lair of the Shadow Broker DLC screwing up imports, several lines Liara says if you romanced her in Lair of the Shadow Broker never play, and can only be accessed through modding saves to fix these erroneous flags.
Similar to the Mass Effect 2 example, there is cut audio in several instances during the Rannoch arc suggesting Tali was intended to be a romance option for Female Shepard at some point in development. Most notably the flirting during the Geth Dreadnought mission, but it crops up again during the trip into the geth consensus. This audio is fully accessible in game with the use of a hacked save file.
A wide selection of additional heavy weapons that were removed from the game can be modded in for player use by editing the Coalesced.ini file. These include the Particle Beam (which appears to function like the Particle Rifle from the From AshesDLC), the Avalanche (fires blasts of cold energy), the Grenade Launcher, the Hydra (fires cluster missiles) and the Arc Projector. It has been suggested that Bioware removed heavy weapons from the game because they broke the plot - but being used in one minor Hold the Line sequence on Earth means that game balance was the more likely answer, especially considering that multiplayer characters get access to Cobra rockets that make the Cain look like a firecracker launcher in terms of damage (though not explosion effects). In addition, several weapons and armours (including the PC-exclusive M-90 Indra sniper rifle, the Collector's Edition N7 weapons, two unused N7 armors and the Warfare/Reckoning/Battlefield armors) are all on-disc, but most had their access methods removed so they could function as pre-order bonuses, and were later distributed in the DLC proper.
The entire Snow Queen Branch of Persona was removed from the U.S. version of the game. This is a major plot branch which leads to an alternate ending. This is still in the game files, and certain lines have been translated (although most text is in gibberish), meaning that Atlus was at least partway through adapting this portion before removing it. It was finally made available to U.S. gamers in the PSP remake.
A user by the name of Dunkelzahn1 uploaded a few videos of Persona 4 in which we can see unused scenes for some Social Links, incluiding totally different versions for some events and a "flag" system like the one used only in the Naoto Route allowing a Friend or Lovers relationship. Also, some of them cointains traces of early localization, such as referring to the Amagi inn as "Amagisa Ryokan" and Yukiko as "okami" instead of manager.
The Pokémon games usually end up with dummied out stuff when brought to North America.
Apparently, Pokémon Red and Blue was supposed to have 190 Pokémon. Not at all coincidentally, there are 39 different indexes for Missingno. (39 + 151 = 190.) It is currently unknown whether the other 39 designs were used in later generations or scrapped altogether.
There is coherent (i.e. not glitched and apparently intentional) data for a trainer battle with Professor Oak. He was probably the game's Bonus Boss after you fought your rival at the Pokémon League - his Pokémon (Tauros, Exeggutor, Arcanine, Gyarados, and one of the starters note There are actually three versions of this battle programmed into the game, one with each of the starters as the fifth Pokémon on the team; presumably, you would fight the version with the starter neither you nor your rival chose) go up to level 70 and have really good movesets. He can be fought with a Gameshark, but he has no pre- or post-battle dialogue.
Missingno., the infamous glitch Pokémon, is part Bird-type. No normal Pokémon have that type (it could have been scrapped in favor of the Flying type several normal Pokémon such as Pidgey have).
There was a move called Kinesis that no Pokémon could learn. It was given to Kadabra and Alakazam in later games.
Red and Green were to have a female protagonist, but was taken out due to technical limitations. She was later slightly revamped (as in a somewhat different hair style and new clothing), put into the remakes, and named "Leaf".
In Red and Green, players were originally going to be able to use the Pokédex during battle, but this was scrapped due to technical issues.
Yellow has one piece of unused music. What it would have been used for is unknown; a common belief is that it would have connected to the "Hurry, get away!" battle system, although this is unlikely as it's stored in the same sound bank as the Pikachu's Beach and Jessie and James themes. It does sound somewhat similar to X and Y's Victory Road music (excepting updated instrumentation and a time signature change), as many YouTube commenters have noted.
The Safari Zone (from Red/Blue) in Gold and Silver. No wild Pokémon are present if it is accessed, though. However, a ROM hack can implement it easily as the ROM can be hacked to make it accessible by putting a door where it was in Generation I in Fuchsia City, as the data for a door exists but does not work when the tile with the data with it has a wall; the leftover Safari Zone can be hacked in the same manner. In the remakes, there's a Safari Zone, but it's a completely new one in Johto—the location of the old Safari Zone now has a Pal Park.
In Gold and Silver, evidence exists suggesting that you were supposed to get a skateboard instead of a bike. Incidentally, the manga counterpart of Ethan (the games' protagonist) does use a skateboard.
In Pokémon Crystal, we have the Pokémon Communications center, which replaced the one in Goldenrod. It was avalible only in the Japanese version and it let the game connect to the internet through a special mobile adapter. It essentally functioned as the predecessor to the Global Terminal that would appear in the Nintendo DS installments. The servers have long since closed and you can't use it anymore, but the reason why it is in this section is because it was actually translated and partialy implemented into the American release before getting taken out at the very last moment and replaced with a normal Pokémon Center. The remnants can be reached with a Game Shark.
In Generation III, the only way to obtain Berry Juice is to encounter a wild Shuckle in Kanto games (since in Hoenn games, it holds Oran Berry instead). However, the only way to do that is to use the Altering Cave unused data. And since sending items from G2 is impossible, the item is rendered inaccessible outside of cheating in G3 games.
There is actually a little game data in FireRed and LeafGreen for Sevii Islands going all the way up to 24, but only seven (nine if you count the event-only Navel Rock and Birth Island) are actually accessible.
In FireRed and LeafGreen, the Japanese version had e-Reader support for scanning Trainers into the game, with the house they're fought with being in the Sevii Islands and the door being blocked unless a card is scanned in. In the international releases, the door stays shut due to the removal of e-Reader support and hacking to access the permanently blocked door leads to a battle with Archie. The door does not work outside of the Japanese release unless the game is hacked to put the proper warp there. (Due to programming reasons Archie is a placeholder for when no Trainer is scanned into the game, so he always appears in international releases if accessed.)
There was an Ability called Cacophony, which would've functioned similarly to the seemingly-opposite Soundproof. Most likely, it was intended for Loudred and Exploud, but they received Soundproof instead, so Cacophony went unused. Unlike with Kinesis, Cacophony was removed from Genration IV and onwards.
Ruby and Sapphire have hidden music themes resembling those of Kanto and Johto.
Likewise, there are unused themes for the Legendary Beasts from GSC in the code of RSE.
In Pokémon Diamond and Pearl, Arceus is capable of transforming into the "typeless" ???-type used by the move Curse, but there is no corresponding plate. It's only there to prevent a game crash when it changes type. (The fifth generation of games removed the ??? type entirely and made Curse a Ghost-type move, so Arceus can't transform into that type even with hacking.)
There is also data in the games for an item called the "Azure Flute." Using it at the Spear Pillar would have allowed access to an area called the "Hall of Origin" to battle and capture Arceus but the event never took place, making hacking the only possible way to trigger this event. It comes complete with unused music not used anywhere else in the game.
In the European version of Platinum, you could not use the slot machines. You could, however, buy coins which you couldn't exchange for prizes.
Before HeartGold and SoulSilver were announced, users of the Pokésav hacking utility discovered that Pokémon could be configured so their capture data would say that they came from Johto. Curiously enough, HGSS Pokémon traded from a Japanese cartridge into US Platinum has their capture data say "From a Far-away Place," which is similar to, though not exactly the same as, the string for Pokémon in the 3rd Generation that were transferred into the GBA titles from Pokémon Colosseum and XD (they display "From a Distant Land").
Another Pokémon with dummied out curiosities is the Sea Slug Gastrodon - data has been uncovered for it to have other appearance variations different from the East and West Sinnoh varieties.
In Pokemon Mystery Dungeon Explorers, Shaymin and Arceus—two "secret" Pokémon back when the games were released—were originally going to be programmed in. However, they scrapped the idea...but Action Replay codes can allow you to change your leader into a decoy that learns Shaymin's moveset AND a prototype of Seed Flare, and encounter decoys that learn a prototype of Judgement.
Shaymin had an entire substory arc and new area implemented with it in Explorers of the Sky, and becomes a playable team member after completing it.
Explorers of Darkness shows a Time Gear in its title screen in a lava-like place that is never seen in any of the games. If one looks at the monument at the end you can see there is enough space for there to have been one more gear, hinting that the volcano-like area was cut.
Gates to Infinity removed the ability to choose your hero and partner's gender for the releases outside of Japan. This was presumably done because choices didn't actually affect the gameplay or dialogue in any way (Though annoyingly, the translations avoided the previous usage of Gender Neutral Writing, referring to both the hero and partner as "he" on multiple occasions). They did, however, alter Pikachu's appearance accordingly (Female Pikachu have a heart-shaped tail tip), meaning players of the localized versions missed out in a small way.
Super Mario Bros.
Mario & Luigi: Bowser's Inside Story has at least one Dummied Out item, a type of mushroom that can be used on Bowser by either of the bros in battles where they're fighting an enemy he's inhaled. A lot of the Bowser-only enemies were also apparently intended to be able to be fought with the bros as well, since most of them have attack patterns they only use against the bros, like Choombas blowing out smoke that forms either M or L to signify which character they're going to attack and most notably, Naplocks that throw a stack of bricks into the air over the targetted brother that need to be smashed by jumping against them and breaking them, exactly like in the platformers: this specific way of avoiding an attack doesn't occur with any other enemy in the game.
Even the Dark Mechawful (and its .5 powerup thing) are fightable by the bros. Note, these guys are in the deepest part of the Bowser-only final dungeon, but the game works fine until you try to fight Dark Bowser with Mario and Luigi. (Fighting against the Peach castle glitches, obviously. Mario and Luigi vs. Dark Fawful and Blizzard Midbus are untested, however.)
Sprites of all the partners from the first game have been discovered in Paper Mario: The Thousand-Year Door; only Parakarry and Bow show up in the final game, with the former being given less screen time since he only delivers the Mario Bros.' mail at the beginning of the game. Also, name labels were discovered for, among others, Shy Guy, Anti Guy, Mecha-Goomba, and Mecha-Chomp.
Tales Of Series
Tales of Phantasia (PS1): Following the release of Phantasian Productions' translation patch, one of the hackers found some completely done, and completely unused, skits.
Tales of Symphonia has a lighthouse in one early city that you can't enter, because "everyone who goes in it gets sick". It's an obvious sidequest trigger, but no actual sidequest is ever triggered by it. There's also a book later in the game that you're apparently supposed to fill with gossip, but it's completely useless except for filling in the entry in your Item Book. Not to mention the non-functional casino in Altamira, which is a mini-game in the PlayStation 2 Japan-only re-release: this was obviously the original intent, before they ran out of time and/or money.
In the Derris-Kharlan prison, there is a teleporter that apparently has no function, making the short corridor to it a waste.
In the sequel, the final battle(s) have lines that were recorded, dubbed into English, and left out of all versions of the game. First of all, there's unique Boss Banter for each member of the first game's party, which trigger when that person is the first in your team. However, they decided to make it impossible to put anyone but Emil or Marta in that slot, so you can't trigger it without hacking. They're real cool, so it's too bad. Secondly, there is a special version of the quote used for Emil's Mystic Arte that is never used. Fans have speculated that Red Eyed Emil was supposed to be able to use the Mystic Arte, with that quote, in the true final battle, but for whatever reason, it was cut. It's pretty obvious that they were last-minute cuts, because all the voices are fully recorded, and they even have the English dub done.
Also, more hacking revealed that Flynn and Repede have full field-screen animations (that is, running around and using the Sorcerer's Ring). Flynn is in your party for the grand total of one battle and leaves before you regain control, and the game never allows you to select Repede as your party leader. The PS3 version changes both of these factors: you can control Repede on the field screen, and Flynn becomes a proper party member at various points throughout the game.
Tales of the Abyss had extra Artes for various characters (such as Asch's Binding Doom, Dist's D-Buster, Anise's Valkyrie Saber, and a couple others). All of them were even dubbed in the US release, but never made it to the final game.
It's common for demos to block off some features without completely removing them, leaving them accessible only through cheats or exploits. A bit of map finagling in Arcanum's demo permits players to leave the roped-off starting area and explore the rest of the world (although it's very boring and most of the enemies are invisible).
Breath of Fire: A dummied out item exists in the code called the "Dr Warp" (it's even in the manual and on the item list), and if you hack it into the inventory, you can use it to access dummied-out areas of the game, as seen here. There is a bar in Nanai that is normally inaccessable, probably due to the Censorship Bureau; the entire town is inaccessable during the day, and the bar door is blocked at night. If you Dr Warp into it, it looks rather unfinished, and has a music that is not heard anywhere else in the game. There's also another unfinished building in Nanai, and a Minus World-like unfinished Dragon Shrine.
Two music tracks, Singing Mountain and Battle 2, were never used in the game itself. They were included on the soundtrack CD, however. The DS remake included new bonus dungeons that use the music themes.
If one were to make use of the "Walk Through Walls" code via cheat device in the original SNES game, walking through the bookshelf in Schala's room resulted in the screwy graphics, then your party ends up in an elevator in the Water Palace dungeon with Magus in your party. Even if you chose to kill him in the game. Something was written in that spot, but who knows what.
That would be the site of the "Zeal Dungeon", a dungeon of unknown purpose present in that same area in a pre-release version that's been floating around the internet for a while. The pre-release also reveals several more things of interest that were removed, such as maps and a world map graphic for the infamous Singing Mountain (present in 65,000,000 BC), a coliseum-like building on the 2300 AD map (which contains no corresponding maps anyone has found), and an entire structure using graphics from the Ocean Palace underneath the Forest Ruins near Medina in 1000 AD.
There are also a few weapons that were dummied out, including a weapon for Lucca that cuts an enemy's HP in half (although it's a bit glitchy sometimes, or possibly it just doesn't work on certain enemies), that can be accessed via save state editing and such.
In Dark Cloud, you can't access the back floors in one dungeon because the keys were left out of the U.S. release.
Dark Souls has a lot of dummied out dialog, items and quests showing What Could Have Been. There are also a few items that were dummied out that can be obtained by hacking your save file, such as the Elite Cleric Set and the Mage Smith Armor.
In Dragon Age: Origins, several of your party members have dialogue and scenes which are not seen in the game but can be restored by mods. For example, party member Morrigan asks you to kill her mother and then retrieve a certain item. A cutscene had been animated and voiced for when you return with this item, but without mods, you never get to see it and the item simply acts as an ordinary gift.
Jowan, the mage who poisons Arl Eamon, has a quest that was supposed to be triggered if you send him away after freeing him. The quest, which consists of meeting him again in the wilderness, was scrapped, but the code still exists, and can be restored by a mod.
At one point Jowan was planned to be a fully playable party member rather than just a temporary one in the Mage origin. Unused dialogue indicates that the player would have saved him using the Right of Conscription, and the Blood Magic specialization would have been learned from him instead of the Desire Demon who teaches it in the final version. Traces of this exist in the released game; Jowan is the only temporary party member to have a colored background in his portrait (all of the other temps use plain black) and if taken into the Fade he can level up there unlike the other Guest Star Party Member Irving.
Loghain and Alistair have banter in at least one scene during the Return to Ostagar DLC, which suggests they weren't always intended to be Mutually Exclusive Party Members. Use of the developer console is required to see it, but it's still buried in the game and it's fully voiced content.
Shale the golem was cut from the game and turned into DLC, with a different recruitment quest. Originally, Shale, Wilhelm's house, and the control rod were all meant to be found within Redcliffe Village. A fan mod restores most of the content, including dialogues with Lloyd and Bella in the tavern, but Shale still remains unrecruitable unless you own The Stone Prisoner DLC; the mod will get you as far as obtaining the control rod, but you'll still need to go to Honnleath to use it.
Eye of the Beholder has teleportation doors with eight symbols that come in pairs: the door with the "orb" symbol will take you to the other "orb" door on another level, and so forth.. You will find a corresponding activation key for seven of them. The eighth is the stone gem, which cannot be found in-game (although you'll get it in the sequel). Level editing reveals that the very first level has a disconnected and empty area, which contains the second portal for the stone gem.
Fable I contained model information for a dragon (which only appeared in the expanded version, The Lost Chapters). Likewise, the demon door which kicked off the expansion could be found, but not opened.
The Commodity Dealer window in Freelancer shows the prices of the local merchandise in a stock exchange-like ticker; this is because the economy was originally supposed to be dynamic, with prices changing according to the laws of economy. The game had been promised to be a lot more similar to the X series than it ended up being; it was supposed to contain a dynamic economy, trading as an actual gameplay mechanic, possibly the ability to own stations and/or buildings and generally to do whatever you liked. Time and budget constraints, sadly, caused much of that to be left out. As it was sold, Freelancer was a combat simulator with a very simplistic monetary factor that only influenced the gear you could buy.
Golden Sun had quite a number of dummy items in the game data, apparently removed for the sequel. It's possible, with a password editor, to put in those items in Issac's party for The Lost Age. Some are merely dummies. Others... well... How does multiple Sol Blades and Masamunes sound to you?
Also, the sequel, The Lost Age, had several Psynergy dummied out. Through hacking, you can use these Psynergy in the game, but there's nothing that will react to them... except interestingly, some things in the second Test Room.
The Lost Age also had several monster lines with only two forms... because the third form was dummied out (second and third forms in the case of the seemingly-unique Wood Walker). Hacking the game reveals sprites, names (translated names, even!) and placeholder stats. Some of these creatures, despite being dummied out, can show up as Summon Magic usable by the Beast Lord classes, and some became proper enemy monsters in Dark Dawn.
The GBA version of Harry Potter and the Prisoner of Azkaban has remnants of a Tapper clone floating about in the data. You can cheat your way into it, but its Unwinnable, as the "catch the mug" routine was either removed or never finished.
Kingdom Hearts: Birth by Sleep had levels from The Jungle Book and The Sword in the Stone that were planned to be in the final product, and even have remnants left in the code (mostly of The Jungle Book world...The Sword in the Stone one must have gotten axed very early in development.) Proof here.
In Lands of Lore3, eating a rifthound's heart will make a few random items appear. Once in a while, items will appear that can never be found normally in the game.
Magi-Nation, due to being rushed to release, has some dream creatures (mons) that are referenced in dialogue and listed in shops, but don't actually appear, and can't be obtained without a Gameshark. Rather frustratingly, this includes a couple legendaries, and some creatures that do appear require ammanite from the lost creatures, so they can't be obtained either.
There are even a few items that hold no purpose, such as the Ornate Awl, and the Feather items.
In the fan-made RPG Maker game Mega Man: The RPG, there are at least two cases of this:
In the equipment screen, there is a slot for shields. At no point in the game do you actually get anything to put in that slot. It's all that is left of the author's intentions to put Proto Man in the game.
This probably has more to do with the fact that RPG Maker's equipment screens have a Shield slot by default, and there's no actual way to remove it.
Might and Magic VII was, at some point, intended to have Manticore and Scorpicore monsters. They were never finished, and lack a model, but while they do not spawn in any of the regions, they can show up in the Arena — which is rather problematic, because lacking a model they are invisible and the game crashes if you try to check how much health they have left.
The code for Might and Magic VIII includes three skills from the game before that cannot be learnednote And one of them is even useless if one edits a savegame to have it, since it makes you better at using a category of weapons that was properly removed from the code, all two examples of it. There is also a Druid Circle dungeon in Murmurwoods, filled with dangerous monsters and with a quest item called a "Druid Circlet" in it. A quest item without a connected quest, and that is not a wearable headgear. The most common theory it that it was supposed to be part of a Druid promotion quest, before the Druid class got axed.
Mother 3 has a ton of dummied out content. Not just enemies, but sprites, musics, cutscenes, backgrounds, lines of text... However, given that the game went through Development Hell and through a ton of changes to its storyline, this is to be expected.
Several enemies that were cut out of the game were discovered by the hackers while working on the translation patch.
In addition, both EarthBound and Mother 3 contain several unused background layers. Though most of the dummied out backgrounds contained in EarthBound are just palette and/or transformation swaps of existing backgrounds with a few exceptions, Mother 3 seems to contain a series of backgrounds intended but not used for the final boss (warning: could be considered terrifying)
There is also an unused cave error that has several sprite layer issues. (If you walk to close to a certain wall you can see the individual tiles going over the lead character.)
The alternate graphic "tile-set" for NetHack features a few tiles that never actually appear anywhere in the game: a Beholder from Dungeons & Dragons is perhaps the most noticeable example.
With NetHack being open-source, you can look right at the source code and find many "deferred features" that aren't in the game at all yet but are at least partially coded. The Beholder, for example, is actually in the source already, but there's no code for its gaze attacks yet. See here for a list. SLASH 'EM does, in fact, add in the Beholder.
Neverwinter Nights 2 has several examples of this. Almost every companion has at least one unused scene that reveals more about them or expands their side-quests. For instance, Qara's side-quest with an elemental trying to kill her was supposed to be much more detailed, and include an implication that she could potentially be a greater threat than the king of shadows.
A particularly missed pair of sidequests are the ones involving Bishop and Neeshka, who only get half a quest each about romance in the finished games
Using the NWN toolkit to examine the expansions for the first game, you can find (and restore) some dialogue/action choices that were dummied out apparently at the request of Wizards of the Coast. One such option let you sell a kidnapped baby to a Red Wizard as a slave. Hilariously, you can still kidnap the baby, but there's nothing else you can do with him... at least until Hordes of the Underdark. In which you may insert the baby into a console and get summonable Drider, a dark elf with the lower body of a giant spider. Squick.
In the Nobilia marketplace in Secret of Evermore, an old man will give you the magic gourd in exchange for the chocobo egg. The egg boosts your max hit points. Not even the game developers can remember what the gourd is supposed to do, and its description certainly doesn't give any clues.
A deleted cut scene in Shin Megami Tensei III: Nocturne had the Demi-fiend meeting with Lilith, who after talking to him would open up a door to a bonus dungeon. This was scrapped in favour of the Labyrinth of Amala.
Septerra Core. Early, pre-patch release versions of the game had one more card slot than there were cards. This caused some people to believe that they were missing a card, and scour the game for the (non-existent) card. It is, however, still believed that there was a card meant to go in that slot at one time, but it got cut or combined with another card.
In Skies of Arcadia Legends, Pinta's Quest is dummied out. It's meant to be played on a VMU (a Dreamcast memory card/handheld console hybrid), so this makes sense, but a lot of the items are still available in-game and their descriptions still have some information about the quest they're made for.
Sonic Chronicles had a series of five events planned that one could attend to unlock one of five exclusive Chao - one for each event. Events two through five were cancelled due to lack of attendance at the first, so only one of the five Chao (Stugs) was made available to Western gamers; the other four, Pooki, Farfinkle, Fimbley, and Baki, were rendered inaccessible without hacking devices. The Japanese release of the game added in button codes to unlock Stugs, Pooki, Fimbley, and Baki (but not Farfinkle).
The original Star Ocean for SNES was so rushed that most of the final dungeon and world never got made, making it seem very unfinished. There's also a door in Van Castle which dialogue indicates is meant to be opened, but can't be in the game. There are dozens of items and enemies (including an instrument, the Shamisen) that are in the code but can't be found, several abilities, and even remnants of code for an unused character. The remake for PSP recreates most of the things that were unfinished, including the hidden character Erys, Joshua's sister.
Telefang has at least a couple of dummied out things:
The Human World, the area at the beginning of the game, was meant to be larger than what the player can normally see in the game. The whole area has plenty of buildings (albeit locked), including two of which are large and have unique graphics not seen anywhere else in the game, but the player can only see a small part of this area at the beginning of the game.
Telefang also has unused Super Game Boy features, including an awesome border (depends on the version you're playing) and a few color palettes (and many more unused ones). 
The Tomb of the TaskMaker, the sequel to the 1990s Mac RPG TaskMaker, had five dungeon names hidden in the coding: Paradise Keys, Black Rose Pyramid, Backgate, Splinter, and Reduce. The names can be seen in ResEdit, or invoked by creating a passageway to them if one is a Master (they just lead to nowhere). There are also several inventory items hidden in the coding, such as the aforementioned Paradise Keys (a special set of keys). These cut corners are the result of Tomb being rush-released. Two of the dummied-out dungeons were added to version 1.0.1 alpha 3, and a couple more were coded in, but can't be accessed unless you beome a Master and hack in entry points.
Certain quests in Ultima VII such as restoring the shrines of virtue had to be patched back.
With Exult's tools you can find bits and pieces of unused assets. For instance, the guard sprite has frames where it is blowing a horn, and there is a separate sprite for flying gargoyles.
Ultima VII Part II has a large number of hidden and incomplete areas that can be found with the teleport cheat. These include a few empty dungeons as well as a copy of the initial area with a staircase leading to a mountain top, and an infinity bow.
Origin continued this trend with Ultima VIII, the most glaring example being the birthplace of Morien and the double doors (see below). In the former case, the patch tried to fix but in doing so created a severe inconsistency in the plot. Some promotional material for the game also included images of the undead attacking Tenebreae. This sequence is in fact still in the game but the flag to activate it cannot be triggered without cheating.
The aforementioned doors: these giant doors that were completely unopenable. Apparently they were supposed to be accessible once you got the expansion that never got produced. And if you use a cheat to move the doors out of the way, you'll find that there is no trigger behind them that would transport you to another map.
Vampire: The Masquerade – Bloodlines was originally supposed to have a "Histories" system, wherein the player could affect point distribution or XP costs at character creation. For instance, a Ventrue (which usually gets the most points in Social Attributes) could select the "Union Leader" history to make Physicals the primary Attributes, or a Malkavian could take "Doomseer" in order to get greater benefits from Auspex at the cost of Obfuscate. The code's still there and can be activated easily, but it's not something that comes with the game automatically.
Xenogears is infamous for having a whole disc dummied out, yet some data from it remains, like cutscenes that you cannot see during the course of the game, bits of script, places on the world map that cannot be accessed, and it seems that it was intended to make the whole Lacan flashback a playable part of the game and not a bunch of cutscenes: more informationhere.
A completely finished music video featuring the game's main theme was removed from the game.