The Sol Dimension was originally coined as such by an unknown editor at the Sonic News Network — officially, it was only generically known as Blaze's world, contrasting Sonic's world. It was picked up by the Sonic the Hedgehog Sticker Collection.
Cash Cow Franchise / Adored by the Network: Even after Sega got out of the console business, it's still Sega's premiere franchise, and one of the very few of their original series that still has games regularly made for it, and it has the most supplemental material and tie ins out of all their series.
Sonic the Hedgehog 2 had a lot of content cut from it to meet the deadline, most famously the Hidden Palace Zone. There are also some nasty glitches that occasionally pop up, such as triggering Super Sonic at the end of a level locking the game in place and forcing you to reset it.
Sonic Spinball was hastily made in six months as a holdover game, since Sonic The Hedgehog3 was taking longer than expected to finish. The game didn't turn out bad at all, but it does have an unpolished feel to it as a result.
Sonic The Hedgehog 3 was such an ambitious game, that it became clear that it would be impossible to finish it as a whole in time, forcing Sega to split the entire game in half, and even then Sonic 3 arrived later than expected (February 1994), with Sonic & Knuckles arriving eight months later with its Lock-On Technology added to allow Sonic 3 to be played as it was originally planned. It didn't help that McDonald's, who had a tie-in deal with the game, ended up pushing Happy Meal toys before the game was released, forcing Sega's hand in the entire thing. On top of that, both games are loaded of glitches and polish issues, some of which are game breaking, to the point where the manual had to handwave these issues (such as Sonic being liable to accidentally get stuck in certain scenery or Tails sometimes being unable to complete Hydrocity in standalone Sonic 3 due to the screen locking up) as "diabolical traps" set up by Robotnik.
Sonic R was obviously rushed to give the Saturn a Killer App, and it backfired—while there aren't a lot of obvious glitches, there are only five race courses, the controls handle poorly, and the racers are poorly balanced. There is also a bug in the Saturn version (fixed in the PC and Gems Collection port) of the game that got corrected in later releases that creates an odd example of Fake Longevity: if you complete a course with the Chaos Emeralds, all the Sonic medallions, and finish first (which is required to hold onto the Chaos Emeralds after the race ends), you go onto fight the course boss as usual but when that race is over, it negates the first place victory you won in the original race and you can't keep the Chaos Emerald(s) you collected. Thus you have to redo the course to get the Emeralds (meaning there's no point in trying to do both things because they're mutually exclusive).
Sonic Adventure was rushed for its original Japanese release and was loaded with glitches, forcing Sonic Team to delay the U.S. release by a year to patch it up. Even then, the game still has loads of glitches, so it's very easy to break wide open, most notably in the DX port, which adds even more glitches than the original Dreamcast game.
Sonic the Hedgehog (2006) is by far the most infamous instance of this, although information of its development made it clear it had the deck stacked against it—Sonic Team was forced to develop the game with half of its usual manpower—Yuji Naka had just left Sega and the other half of the team was busy working on Sonic and the Secret Rings, which was made to make up for the fact that Sonic 2006 was impossible to port to the Wii, and they had to make the game for two advanced, brand new consoles. On top of that, Sega wanted the game out in time for Sonic's 15th Anniversary, so Sonic Team was forced to rush the game out the door and disregard bug testing and quality assurance. The final result was a game that left a black mark on the series and Sega's reputation forever, and one of the most infamous video games ever made.
The 3DS version of Sonic Generations, which was rushed out in about six months or so, compared to the console versions which were in concept since at least 2008. While the final product certainly wasn't a disaster by any stretch, it lacks content compared to the console versions and it's obvious that some corners were cut (including the rival races, which take place on improbable stages).
Cowboy BeBop at His Computer: There are a small number of fans who, be it out of ignorance, research failure or a schism between fans of the newer and older games, take the dub induced naming scheme of Robotnik having the nickname of Eggman with his real name put off to the side as meaning they're both two separate charactersnote Ironically, this is the case in the Archie Sonic comics, because the old Robotnik and new Eggman are in fact two separate characters, the new one being an alternate dimension counterpart of the former, with a similar enough backstory and personality to where he serves as an interchangeable replacement with the original Robotnik, who was permanently killed off in issue 50 and, as of the timeline reboot, literally erased from ever existing. This also saved the writers the trouble of giving exposition about the two different Robotniks, which they felt would risk confusing or alienating new readers., or, if they're really, really on the ball, say that Robotnik is Eggman's grandfather, both of which are completely contradicted by canon, not only because it's blatantly two names of the same character, but because Eggman already has a grandfather in canon—whose surname is Robotnik granted, but Gerald is obviously a separate character from his grandson Ivo in both appearance and personality (both before and after his tragic descent into veangeful madness), and had died long before Sonic was even born.
Tails used to be voiced by young boys, but since Sonic X, he has been voiced by women. In the Japanese versions, he has been voiced by one single woman since Sonic Heroes and Sonic X.
Creative Differences: Tom Kalinske, former CEO of Sega of America, said in an interview that he believes that Sega of Japan hated all the changes Sega of America was making to the series. He states that Sega of Japan resented that they had "softened" the character, as Sonic was originally envisioned as having sharp teeth, a busty girlfriend and was the front for a rock band, but Sega of America changed his appearance to better market the series globally.note Ironically, it would be the western Sonic shows and comics that would establish the character as a rebellious but heroic teenager who loved rock and roll. Furthermore, Sega would later make a rule stating that there would no true romantic couples in the Sonic franchise. Kalinske also believes that this resentment is part of the reason why the series had a weak presence on the Sega Saturn despite its massive western audience.
The director of Sonic Adventure 2 was so angry at the negative reception for Big the Cat in the previous game that he took personal offense to it and put Big the Cat as a hidden secret in every stage as a spiteful act of vengeance towards everyone (curiously, almost all of Big's cameos ended up being removed in the GameCube port and then turned up again in the HD remakes).
Mild, but Yuji Naka said that he feels the more recent Sonic games aren't as fun as the older ones, his main complaint being that they're too easy.
On the subject of the newer games, the new development staff of Sonic Team admitted in Nintendo Power in a preview feature on Sonic Colors that the were-hog elements of Sonic Unleashed and the swordplay of Sonic and the Black Knight were not good ideas; and based Colors largely around the well-received day stages of the former.
Sonic Team openly despised the early American "Mohawk quill" redesign of Sonic featured in box and promo art, even seeing it as redundant because Sonic was designed to appeal to western audiences in the first place, and only relented when they felt that it and other Americanized changes to the series did help Sonic get off the ground in the long run. It became a moot point when the redesign was retired in artwork in favor of the original Japanese design by the mid 90s.
Creator Killer: While going through the disastrous production ofSonic X-treme, Chris Coffin, the games lead programmer, contracted pneumonia from overworking to try and get the game finished in time, and he was told he had 6 months to live, forcing him to drop out of the project. However, he survived and continues to work on video games as Christina Coffin. The game's turbulent production and cancellation also led to the company making it, the Sega Technical Institute, getting dissolved.
After Sonic Boom: Rise of Lyric proved to be a critical disaster and an embarrassing flop at retail (it's the absolute worst reviewed Sonic game on Metacritic, with its metascore being even lower than Sonic 06, was outsold by two other Sega games note Alien: Isolation and Football Manager and didn't even break into the top 40 sales chart in the UK), and combined with many staffers leaving or getting fired during its turbulent production, it seems unlikely that the fledging game company Big Red Button Entertainment will ever make another game again.
The unfortunate cause of Sonic X-Treme's Vaporware status, as well as the replacement of all the game voice actors with their Sonic X counterparts.
Executives often meddled to get games out for a Christmas release. It happened, but not too consequently, in some of the classic games. The original Japanese Sonic Adventure was particularly buggy, and that's why they made a re-release there with all the fixes made in the English version.
This is the reasoning behind the unfortunate state of Sonic 2006 also; it was rushed out to release in time for both the Christmas period and Sonic's 15th Anniversary, and as a result is wrought with bugs and is quite obviously unfinished.
The reason Classic Sonic rarely appears in newer games is because Sega has a mandate that Modern and Classic Sonic can't appear alongside each other unless time travel is involved (such was the case with Sonic Generations and Sonic Forces). Classic Sonic was considered for an appearance in Sega & Sonic All Stars Racing Transformed, but Sega shot it down for this reason. Their style guide also says that Classic and Modern Sonic artwork cannot be combined in any product.
Fandom Life Cycle: Has hovered around Stage 5 (full mainstream status) since the beginning, even though it is not as big as the in the early 1990s.
Fan Nickname: Several over the past two decades, but the most recent and most amusing nickname Sonic has been referred is "Generic Sonic", as his current design is referred to in the coding for the Generations demo.
Sonic himself, despite being made as a direct competitor to Mario, was unmistakably inspired by it. Although the series did maintain its own feel instead of being a mere copycat, recent games such as Sonic Lost World clearly show an attempt to emulate elements of the Mario series, Super Mario Galaxy in particular, while mixing it with the series standard gameplay elements.
Franchise Killer: The franchise has somehow managed to avoid this despite the reception of most of the modern Sonic games (due to him beingone of Sega's few cash cows). That said, all of his spinoffs have been given the axe over the years, to the point that only the main series of games are keeping the series afloat. To wit:
There were only two games in the spinoff Storybook Series, as Sonic and the Black Knight failed to impress.
After years of dormancy, the original "classic" branch of Sonic The Hedgehog games that kickstarted the franchise on the Sega Genesis was given a new installment through the downloadable Sonic the Hedgehog 4 series, beginning with Episode I. The game received relatively positive reviews from critics and sold well enough to get a second episode greenlit; but also split the fanbasefor the changes it made to the legacy gameplay and recycled content, and was widely declared by fans of the Genesis games (andreviewers in retrospective pieces) as a disappointing sequel. The Hype Backlash was so great that Sonic Team, prior to Episode II's release, said Episode II's reception would determine on whether they would continue the series. Needless to say, Episode II was released to critical and commercial indifference, which led to a planned third episode being canned and the classic series (once again) sent to an early grave.
After Sonic Rush Adventure underperformed in sales, all handheld Sonic games since then have been handheld counterparts of Sonic Team's console games, rather than their ownindividualseries, something the franchise hadn't completely done since the Game Gear port of Sonic Spinball.
The Sonic Riders line of racing spinoff games was killed off by the Xbox 360/Kinect-exclusive third game Free Riders (though it's possible that with the advent of the Sega All-Stars line of racing games, Sega likely had no plans to continue past the third game anyway). The game was roundly ripped apart by reviewers and fans alike for its atrocious control scheme that was (poorly) designed to utilize the movement of the player's entire body for input and was the only method provided for playing and navigating through the game (compared to the previous two games, which used traditional controllers and used or offered traditional control schemes).
Sonic Boom: Rise of Lyric was a critical disaster and an embarrassing flop on release—to date, its the worst reviewed and worst selling major Sonic title yet at around 300,000 units sold worldwide—even the slightly better received DS spinoff, Shattered Crystal, only sold a paltry 200,000 units. To put this in perspective, Sega's headlining franchise was outsold several times over by another Sega title from the same year, Alien: Isolation at around 2,000,000 units worldwide. It killed the company that made it (Big Red Button Entertainment), and there are currently no plans for more console games in the Boom series. The comic book adaptation for it ended after a scant eleven issues. The only hint of it surviving is a delayed DS follow up called Fire and Ice, which is being developed by Sanzaru Games, and its tie-in cartoon getting a second season.
Franchise Zombie: Sonic is the poster child of this in video games. The majority of the original Sonic Team staff that worked on the well-received Sonic games for the Sega Genesis (including the original three creators of the series-programmer Yuji Naka, character designer Naoto Ohshima, and game director Hirokazu Yasuhara) have long left Sega, and none of Sonic's games released since then have reached the heights of those games, specifically due to the franchise's inconsistent quality ever since it transitioned into 3D gameplay. The series is still around due to its status as a mascot for Sega and being the publisher's few cash cows, thanks to the franchise's persistent fanbase continuing to support the games enough for them to turn a profit while always declaring that the next game will be the one that finally "brings Sonic back". This is despite Sega releasing gamesthat manywould argue should have put the series in its grave years ago (with Sonic 2006 and Sonic Boom: Rise of Lyric in particular frequently cited as two of the worst video games ever due to their numerous technical issues and poorly-received gameplay). Even Sega's attempts at revitalizing the 2D platformer branch of Sonic with Sonic the Hedgehog 4 were not as well-received as the Genesis games with critics and (especially) by fans. In fact, the series showed signs of being a zombie even before the original creators left the series-after the series hit its peak with Sonic 3 & Knuckles, Sonic Team focused on makingoriginaltitles; whereas Sega tried to continue the Sonic franchise without them to no success. After Sega Technical Institute's Sonic X-treme -Sonic's intended Video Game 3D Leap on the Sega Saturn- failed to make it to shelves, Sega finally got Sonic Team back to give the series a proper 3D title for the Sega Dreamcast. note Even then, Sonic Adventure (which had Naka and Ohshima on board) was the last game with any of Sonic's creators working directly on a Sonic game. Ohshima left Sega after Sonic Adventure finished development in 1998 to form Artoon, largely due to a strained relationship with Naka over the series' direction. Yasuhara didn't participate in Sonic Adventure because he had quit Sonic Team after Sonic 3 & Knuckles - for the same reasons Ohshima left Sonic Team - ultimately leaving Sega for Naughty Dog in 2002. Naka himself left Sega in 2006 to form Prope as he was tired of being stuck with (executive) producer roles for original IPs made by Sonic Team.
Genius Bonus: Planet Mobius was named for the Möbius strip, a reference to the loop-de-loops founds in the original Sonic game and its sequels. Neat, eh?
Keep Circulating the Tapes: The bulk of the original games have seen a rerelease in some form, but there are a handful of titles that haven't and probably won't get ports anytime soon, including Knuckles Chaotix (likely due to Sega not wanting to waste time coding a 32X emulator for one game) and the arcade game SegaSonic the Hedgehog (the reason that is often given is due to the original machine having a unique control input that would be hard to mimic on a keyboard or controller).
Killer App: The original Sonic games for the Sega Genesis, and arguably the Sonic Adventure games for the Dreamcast (at the time).
Mid-Development Genre Shift: The initial concept was a more traditional platformer with puzzles and exploration akin to Super Mario Bros. 2. The final product, while still a platformer, focused more dominantly on its now trademark speed. This evolution is even more prominent in its sequel.
This trailer showing clips of the various Sonic console games throughout the years, with Sonic himself looking pretty exasperated once they get to Sonic Heroes (around the time the critical backlash of the games began). Also, much more polished beta footage of '06 is used, as well as only the daytime stages of Unleashed. However, Sonic and the Black Knight is completely omitted from the video, whilst its predecessor, Sonic and the Secret Rings notably wasn't.
Jon St. John voiced Big in Sonic Adventure, Sonic Shuffle and Sonic Heroes. He later regretted doing so, going as far as deliberately forgetting how to do Big's voice just so he wouldn't get any call backs.
The Other Darrin: The series has gone through a veritable revolving door of voice actors throughout the years, some more controversial than others. Tails, in particular, has gone through more voice actor switches than any other character. In both the English AND Japanese versions.
The reason the original Sonic the Hedgehog theme is so rarely heard is because the rights to the song are owned by Dreams Come True, and Sega has to pay royalties to them for using it. They almost ran into trouble with this in Sonic Spinball, which originally used the theme without authorization from Dreams Come True under the assumption that Sega owned the song—they found out it was not the case just days before shipping, so the song was hastily Dummied Out of the game and replaced with new music.
The vocals for the japanese Sonic CD soundtrack were replaced with instrumentals for the HD port due to unforeseen legal issues regarding the rights to them.
According to Cirocco Jones (mistakenly credited as Scirocco in the Sonic 3 credits), there's a huge legal mess concerning the music used in Sonic 3 & Knuckles, likely due to unpaid royalties, improperly crediting the musicians, or (as was the case with Dreams Come True), licensing issues. Considering that two of the music composers (Michael Jackson and Brad Buxer) directly sampled songs from their respective discographies, the latter is the most likely. It's generally believed this is the reason why a Taxman/Stealth remaster like the first two Genesis games is unlikely, as Sega has only been able to release direct emulations of the original game or recoded versions with different music (as seen in the PC version).
Sega was forced to put a legally mandated embargo on elements and characters of certain Sonic games and series from being used in each other (for example, characters exclusive to the SatAM Sonic cartoon and Archie comics are barred from appearing in the games, and even characters from the main games like Eggman Nega and Black Doom were barred from comic appearances) due to Sega of America and Sega of Japan having separate copyrights on elements of the Sonic series, as well as other studios that co produced certain Sonic works, like TMS and 4Kids having their own stakes with elements exclusive to series like Sonic X.
Sonic the Hedgehog 2's own history can be chronicled by the various Alphas, Betas and Deltas made along the way. Rumor had it that 2 was supposed to utilize Time Travel, but it proved way too complicated for the simplistic Sega Genesis. Many Zones were planned and removed, including a curiously named stage called Genocide City and the legendary Hidden Palace Zone (which was much later restored as a secret level in the iOS remake). Sega gave Nickelodeon a very early version of 2 for Nick Arcade. The game's production (located in Sega Technical Institute's headquarters) was also notorious for language barriers and conflicting work ethics between Japanese Sonic Team members, who Naka brought to the United States to work on the game as he was unhappy with Sega of Japan's policies; and the American STI members, who assisted in the game's development. (Understandably enough, Naka developed Sonic 3 & Knuckles in STI on the condition that only his fellow Sonic Team members and other Japanese STI staff would develop the title to avoid another instance of this.)
An HD Fan Remake of Sonic the Hedgehog 2 was cancelled in 2012 when the lead programmer, LOst, had Creative Differences with the rest of the team and provided a build of the game with DRM protection. Since he had not released the source code for the game's engine, the game could not be updated. Production resumed in 2014 when a fan of the project developed a replacement engine.
Sonic & Hedgehog 3 and Sonic & Knuckles were once planned to be one big game, just the basic Sonic the Hedgehog 3. However, time restraints forced Sega to split the game in two in time for 3's release, leaving many fans to wonder what these other stages were once they put in the insanely difficult Stage Select code. When Sonic & Knuckles was being made, the initial plan was that it could hook up to Sonic the Hedgehog 1, Sonic the Hedgehog 2 and Sonic the Hedgehog 3 for new playing adventures. However, complications with the code in Sonic the Hedgehog forced them to scrap it and replace it with the Blue Spheres mini game collection. It was initially said that Knuckles gliding onto a treadmill in Scrap Brain Zone caused the game to crash. However, it was revealed later on that it was because most of the game's graphics was built around Sonic's color palette, and introducing Knuckles would end up changing every other graphic in the game. A fan did a hack years later by reducing Knuckles' color scheme to match the games' limited palette. Due to the introduction of Super Sonic in Sonic the Hedgehog 2, that game did not suffer such problems.
And then Michael Jackson's rumored involvement in the game's music is a whole story of its own, which ranges from anonymous credits and dropped finished tracks because of his child molestation allegations, to him being dissatisfied with the Genesis sound hardware.
According to the PixN'Love History of Sonic the Hedgehog book, the "Time Restraints" problem turned out to be a business deal with McDonald's — McDonald's had set up a deal for Sonic 3-related Happy Meal toys, expecting a Christmas release. However, when that didn't happen, Sega was forced to rush Sonic 3 out with just the six stages. With as big as Sonic 3 was, stage-wise, it wasn't too bad of a strike.
For starters, what would eventually become Sonic X-treme for the Sega Saturn was actually the byproduct of a slew of several failed pitches for a Sonic game developed by Sega Technical Institute, which underwent many ideas for stories, game design, and even platforms (with the game planned for the Sega Genesis, and then its add-on the Sega 32X, before finally being settled for the Saturn).
When development finally got underway, the development staff was comprised of two teams: one for the main levels, led by lead designer Chris Senn and lead programmer Ofer Alon; the other for the boss levels, led by programmer Chris Coffin. Despite the presence of a project overseer -Mike Wallis- to monitor both teams, the two groups ended up practically building two separate games with minimal similarities to each other. Not helping matters were the smaller teams that formed within the main teams and proceeded to work on different aspects of the game's development, who while in theory were supposed to ease the development process made it more cumbersome in practice. This ultimately contributed to an overall lack of communication across the development team, which led to high tensions between both groups, not at all helped by Ofer's seclusive tendencies from the rest of his team.
The development team for the main levels frequently ran into problems porting the engine to the Saturn-the game was originally programmed on a Mac computer, then quickly ported a PC before finally ported to Saturn. While the game ran smoothly on Mac and PC, the Saturn port had atrocious framerate issues, with the game playing at a consistently sluggish 3-4 FPS. This along with the aforementioned rocky relationship within the studio led to constant delays in the game's development cycle.
As a result of all this, Sega of America finally forced their hand in the development process by bringing in third-party developer Point-Of-View (POV for short) to smooth out the development process...unfortunately, this only deepened the cracks that would lead to the collapse of the game's development. Despite POV's intended role being to assist porting the main game's engine to the Saturn, they ultimately took over development duties from Alon — a decision which wouldn't had been so bad if POV didn't prove themselves largely inexperienced to the task. A very basic image of Sonic on a checkerboard background was what POV presented to demonstrate their programming skills (to say Senn and Alon were unimpressed would be an understatement), topped off by the developer also being unsuccessful at porting Alon's engine to the Saturn. Despite this change in the development process, a new group comprised of the main engine's original team was later established by Alon and Senn to continue their own work on the main engine.
This all culminated into a horribly botched presentation of the game to a group of Sega of Japan's representatives — which included then-President Hayao Nakayama — who visited STI's headquarters in March of 1996 to check out the game's progress. While the original team was polishing up their engine for a presentation to the SoJ staff (which had undergone a lot of development and had also been successfully ported to the Saturn), unknowingly to them another presentation with POV's failed attempts to run an older version of Alon's engine on the Saturn had already been shown to the SoJ staff, with Nakayama being disgusted with the results. This was followed by a presentation of Coffin's boss engine in action, which led to Nakayama ordering for the entire game to be designed around that engineand be completed for that year's holiday season. Despite Senn's best efforts to persuade them to stay a while longer to see their newer version of Alon's engine, they ultimately failed to convince the representatives to view the new engine.
As a result, development from this point forward was largely restricted to Coffin's team to finish the game in time for the fast-approaching holiday season deadline, with POV, Ofer's team, and all work on the main engine effectively cancelled from the development process. In desperation, Coffin's team asked for and was granted use of the engine used in NiGHTS Into Dreams... to hasten development so the game would be finished on time. After getting accustomed to the engine's use after two weeks, the engine was taken away due to NiGHTS/Sonic creator Yuji Naka learning about the engine's use (the engine had been taken without his consent) and threatening to quit Sega if the team continued using his engine, sending the team back to square one.note An alternative report that also exists claims that Coffin used NiGHTS as an inspiration when designing the game's levels, of which Naka may have mistaken as his engine being used and Naka's threats leading to Coffin having to scrap the similarly designed levels he had made by that point. All of this resulted in Coffin doing most of the work himself, tirelessly working 20 hours a day and sleeping in the offices. When he contracted pneumonia and doctors told him he had only 6 months to live if he kept working as he did, he was forced to exit development, and thus Wallis being forced to tell his superiors that the game would not be completed in time for Christmas. By that point, there was no other choice but to pull the plug on the game, with an later attempt by Senn and Ofer to get their work on the game released on PC rejected.
Sonic X-treme's failure to show up on shelves has been largely pointed to as a reason as to why the Sega Saturn was a commercial failure, as the hole left in its wake meant that the Sonic series (whose 2D platforming entries sold millions on the Sega Genesis) would not see a proper platforming installment released on the system and left the Saturn without a guaranteed Killer App for its system (not helped by the fact that rivals Nintendo and Sony had brought to the table their own3D platformer offerings for their respective consoles earlier that year). The Sonic series wouldn't receive a 3D installment until Sega got Sonic Team to revamp the series for the Sega Dreamcast. The game's cancellation has also been blamed for developer STI dissolving shortly afterwards.
Sonic Heroes was meant to be on the Xbox and GameCube only from the beginning, but midway through production, Sony apparantly gave Sega a deal to port to PlayStation 2 or be denied any favors from the company forever. Sonic Team's inexperience with the PS2 engine, as well as eventually being ported onto the PC as well, ended in a highly laggy, even boring (un)finished product.
From the segments of information given about its hectic development, Sonic Boom: Rise of Lyric ended up being subject to this. Developer videos and interviews have indicated that the game — running on the CryEngine 3 engine — was originally intended to be developed for Xbox and PlayStation platforms; however, the final game was released as a Wii U exclusive — a platform that CryEngine 3 was not officially supported for. With Sonic Boom: Rise of Lyric announced as the third and final game in Sega's Nintendo console-exclusive Sonic partnership and the game reportedly going gold in July, the general consensus of what presumably happened behind-the-scenes was that Sega ended up rushing the game's development so they could release the game in time for the Christmas season and so they could quickly finish the Nintendo-exclusive Sonic partnership (as the first two games of the deal sold poorly). Not helping matters was CryEngine 3 not able to handle the game that they planned to make (a action-adventure game that supported two player co-op...mind you, CryEngine 3 was originally designed for first-person shooters), with one of the game's developer stating that the team "was fighting against the engine the entire time". And if that wasn't enough, a large chunk of the team left in July either voluntarily or just being let go. As a result, the final game had a whole manner of glitches and visuals that left a lot to be desired — a stark contrast to the early footage released for the game, which showcased impressive visuals. It also didn't help that Sega enforced a review embargo to prevent official reviewers from telling the public about the mess the game was in, not that it did any good once the game was launched.
Sonic went through several character designs before he was settled on as a hedgehog, including a fox, a dog, a rabbit, an armadillo, and a Theodore Roosevelt look-alike in pajamas. Also, his original name was "Mr. Needlemouse" (from a literal translation of the Japanese word for hedgehog, harinezumi). The armadillo idea would later become Mighty the Armadillo, and the rabbit idea is the basis for another Sega game (but with a star instead of a rabbit). Of course, we all know who the Roosevelt man turned out to become. Also, the "Roosevelt" concept was attached to an idea of the hero being some type of "dream warrior" that fought nightmare creatures, likely as a counter to Super Mario Bros. 2. This idea obviously ended up getting reworked over the decade and turned into NiGHTS into Dreams....
Robotnik's original design was actually intended as the design for the hero, until a change in direction. His concept was actually Theodore Roosevelt in pajamas.
At one point in development, he was much larger and not the main antagonist.
Sonic could have had a human love interest named Madonna.
Knuckles was originally going to speak with a Jamaican accent.
Sonic the Hedgehog 2 was intended to involve Time Travel with a Good Future and Bad Future possible but the limitations of the Genesis cartridges at the time of development in 1991 prevented this. About six months later Sonic the Hedgehog CD started development with the concepts intact and was released in 1993.
Sonic 3 was intended to have both Tails and Knuckles as playable characters but, after being rushed for time, only Tails was left in the game planning. You can play as Knuckles when the S3 cartridge is locked onto the S&K cartridge, however.
Sonic & Knuckles and Sonic 3 w/ Lock On Technology were intended to be a single large game, code named Project Blue Red in alpha and beta stages, Sega realized that the cost of producing this one game (which would need to be larger then their own self-set system cartridge limits allowed) would out weight the cost of splitting it down and making two games which could be linked together.
Tails was originally planned to be a Tanuki, but this apparently caused confusion due to the Mario franchise already having the Tanooki Suit, so he was made a fox instead.
Sonic SatAM characters Sally Acorn and Bunnie Rabbot were planned to appear in multiple early projects (including early concepts for Sonic Xtreme), though ultimately have only a brief cameo in Sonic the Hedgehog Spinball to show for it.
According to Word of God, Perfect Chaos's redesign in Sonic Generations was what they orignally intended for him to look like, but due to technological limitations at the time, it wasn't possible.
Both Metal Sonic and an unknown robot resembling a form of Mecha Sonic can be seen in tubes in the Final Egg section of the Mystic Ruins in Sonic Adventure. In Archie Comics, the latter was called Silver Sonic II.
Want to know which version of the original Sonic the Hedgehog you're playing? Check out the clouds in Green Hill Zone. In most Japanese versions, they scroll, but in most U.S. versions, they're static.
Also from the original game, there was originally supposed to be a sound test menu with an animated band "playing" the music while Sonic partakes in some breakdancing. It was nixed so the game could meet deadlines, and its space was replaced with the famous "SAY-GUUUUH!" choir heard at the end of Sega's Japanese adverts for the company logo.
Furthermore, the synthesis player of the band, Vector the Crocodile, would go on to become a supporting player in the series.
Yuji Naka reportedly added the seventh emerald and Super Sonic to Sonic 2 as a Shout-Out to Dragon Ball Z. To make it even more obvious, in Sonic 3, Super Sonic had green eyes.
Also introduced in Sonic 2, the Death Egg was a Shout-Out to the Death Star from Star Wars. Supposedly this was to balance out the Japanese fanservice with some American fanservice.
There's an infamous "bug" in the original Sonic Genesis game where, if you land on a group of spikes after being hit without wearing a shield and without landing on the ground first, you will die regardless of the fact that you're supposed to have Mercy Invincibility, at that point. "Bug", because until recently it was thought to be a bug, and not a preprogrammed behavior. Fortunately, all sequels and future releases of the game eliminate this "bug".
Sonic characters do not have toes. However, in the cartoons, they do. And if Sonic & All-Stars Racing Transformed is anything to go by, they seem to have toe bones despite not having toes.
Amy Rose was originally brown and called "Eimi" in her debut manga, and instead of being Sonic's "self-proclaimed" girlfriend, she actually was his girlfriend (or at least, his Secret Identity). Additionally, Amy is nicknamed "Rosy the Rascal" in the Japanese manual of Sonic the Hedgehog CD as well as her character card in Sonic the Fighters.