Sonic the Hedgehog series

Sonic the Hedgehog is a franchise of video games released by Sega starring their mascot character Sonic the Hedgehog. The series began in 1991 with the release of Sonic the Hedgehog on the Sega Mega Drive / Genesis. An 8-bit version of the game was also released for the Master System and Game Gear formats. Sonic was responsible for turning Sega into a leading video game company early in the 16-bit era, and his first game soon replaced Altered Beast as the default pack-in game for the Genesis in North America and Europe.

As of 2013, the franchise had sold more than 140 million units, making the series the 5th best-selling video game franchise of all time.

Most games in the series are developed by Sonic Team, except some spin-offs that were independently developed by Sega of America. The chief programmer for the first game was Yuji Naka, who would later become head of the Sonic Team division, and the game planner was Hirokazu Yasuhara but stopped producing games for the franchise. The music of the first two Sonic the Hedgehog games on the Mega Drive / Genesis were composed by Masato Nakamura of the Japanese band Dreams Come True.

Yuji Naka, Hirokazu Yasuhara, and Naoto Ohshima soon stopped producing games for Sonic. Yuji Naka became the head of his franchise, Prope. Ohshima joined the company Artoon, and Yasuhara moved to Namco, another gaming company. Currently, Takashi Iizuka is the head of Sonic Team and has been involved in several Sonic games. Most of the music is done by Sega's Sound Team or Crush 40.

Overview
Most games in the series feature a blue heroic anthropomorphic hedgehog named Sonic as the central player character and protagonist. The games feature Sonic's attempts to save his planet from various threats, primarily the evil genius called Dr. Eggman in Japan, and Dr. Ivo Robotnik in Western regions, although he is usually called the former as of Sonic Adventure. The main antagonist throughout the series, Robotnik's aim is to rule the planet and establish the Eggman Empire or Eggmanland (which he succeeded in doing in Sonic Unleashed); and to achieve this, he usually attempts to eliminate Sonic and acquire the powerful Chaos Emeralds.

Two-dimensional (2D) Sonic titles are platform games viewed from a side-on perspective. Their controls are fairly basic and do not deviate much from the genre standard; the selling point of the series is the incredible speed of the playable characters, who usually have the ability to run uphill, walls and even ceilings. They also feature various momentum-based elements, such as roller coaster-like loops and corkscrews. Giant pinball machines with flippers and bumpers, which knock the characters around as concussive balls, are also common. Springboards, which launch characters towards a certain direction (up, left, or right) are regular objects through the franchise too. The stages have several sequences which involve a character being thrown along preset paths with little input from the player. However, there are also numerous sections involving precise jumping between platforms and avoiding of hazards (e.g. Spikes and bottomless pits). The enemies are normally robots created by Dr. Robotnik ("Badniks") and are destroyed by simply jumping/rolling onto them. Power-ups (such as Shields and bursts of speed) are contained in television Monitors and can be obtained by breaking them open. The levels themselves are divided in two to three "acts", depending on the game, and are named "Zones" (rounds in Sonic the Hedgehog CD). Star Posts (Lampposts in the original Sonic the Hedgehog) act as checkpoints once a life is lost, which often allow access to the Bonus Stages after getting a predetermined number of Rings. Goal Plates usually signal the end of an act, always showing a picture of Dr. Robotnik at first, then spinning and changing to one of the playing character once he/she touches it. Special Stages are another common feature in Sonic games, being dimensions far from the games' setting which allow the player to gain Chaos Emeralds, extra lives, and Continues, usually entered through Giant Rings. A boss, an enemy with much higher HP, is often fought in the final act of a zone/round, generally Dr. Eggman in his many machines. After defeating the boss, the player has to destroy a Capsule to free the captured animals to end the level and get to the next one.

Three-dimensional (3D) Sonic entries do not restrict movement as much, controls are slightly more advanced, and the frequency of automated events is increased. These games, while sharing several of the same components with their 2D counterparts, also modify some of those concepts to accomodate them into the 3D perspective. In comparison to the two-dimensional entries, the three-dimensional titles put a greater emphasis on the game's plot and character development.

History


While several people have been involved in the creation of Sonic, the artist Naoto Ohshima, programmer Yuji Naka and designer Hirokazu Yasuhara are generally credited with the creation of the character.

In April 1990, Sega requested a game capable of selling more than 1,000,000 copies; a character who could compete against Nintendo's Super Mario, and a character to replace Alex Kidd as the company's mascot. Several character designs were submitted by its AM8 research and development department. These included an armadillo (who was later developed into Mighty the Armadillo), a dog, a Theodore Roosevelt look-alike in pajamas (who was later used as the basis of the design of the main antagonist Dr. Eggman) and a rabbit (who would use its extendable ears to collect objects, an idea that was later used for a separate Sega character, Ristar). Eventually, the mascot they selected was Naoto Ohshima's submission, a spiky teal hedgehog codenamed "Mr. Needlemouse", later renamed Sonic. Sonic's color was based on the Sega logo, his shoe buckles based on Michael Jackson, his shoe color based on Santa Claus, and his personality was inspired by future-President Bill Clinton's "get it done" attitude, who Ōhshima felt embodied a modern sensibility of wanting to get things done right away, righting wrongs as they presented themselves instead of letting them linger. According to Yuji Naka, Sonic's color also serves to symbolize peace, trust, and coolness (which are the attributes of Sonic's character). His trademark speed is based on Super Mario Bros. World 1-1, with Sonic creator Yuji Naka stating in issue 260 of Nintendo Power that "I always tried to get through the level as fast as I could," which inspired the initial concept for Sonic the Hedgehog. Sonic was created without the ability to swim because of a mistaken assumption by Yuji Naka that all hedgehogs could not do so.

A group of fifteen people started working on Sonic the Hedgehog and renamed themselves Sonic Team. The game's soundtrack was composed by Masato Nakamura of the band Dreams Come True. Sega sponsored the group's "Wonder 3" tour, painting Sonic on the tour bus, distributing pamphlets advertising the game, and having footage of the game broadcast above stage prior to its release.

The original concepts gave Sonic fangs and put him in a band with a human girlfriend named Madonna. However, a team from Sega of America, led by Madeline Schroeder, "softened" the character up for an American audience by removing these elements. This sparked a heated issue with Sonic Team. Naka later admitted that it was probably for the best. Sonic's precise age, weight, height and other physical characteristics vary depending on the continuity in which he appears and the style in which he is drawn. In the video games, Sonic's original design by Naoto Ohshima was with short spikes, a round body, and no visible irises. Artwork featuring this design and drawn by Akira Watanabe was displayed on the package artwork for Sonic the Hedgehog, and most subsequent Sonic video games featured similar designs. When Sonic the Hedgehog 2 for the Mega Drive appeared, Sonic's proportions changed. The original 1:2 head to height ratio changed to 1:2.5.

Sonic the Hedgehog, the launch title in what would become the Sonic series, was released in 1991 for the Sega Mega Drive to critical acclaim and far exceeding Sega's commercial expectations, becoming a sensational hit and giving a huge popularity boost for the company, enough so that Sega could directly compete with Nintendo. The game was soon ported to Sega's 8-bit platforms: the Master System and the handheld Game Gear; this version had similar zone themes and regular enemies, but entirely different level layouts and bosses. It was also well-received by critics.

After the first game's initial success, a sequel, Sonic the Hedgehog 2, soon followed, introducing Sonic's then-new sidekick and best friend, Miles "Tails" Prower. Unlike the original Sonic the Hedgehog, it was developed by the Sega Technical Institute rather than Sonic Team. Released in 1992, the gameplay and story remained largely the same as the previous game. The game also introduced a new ability for Sonic to use: the Spin Dash. While its Mega Drive iteration is more widely known, the game was first released for the Master System and Game Gear, having little to no connection with 16-bit counterpart aside the name. Sonic the Hedgehog 2 was a commercial success, and was released to critical acclaim in all of its versions.

Sonic the Hedgehog CD was released the following year, developed by a different team in Japan headed by Naoto Ohshima. While this game was supposed to be the same as Sonic the Hedgehog 2, during development, it eventually became its own project. Sonic the Hedgehog CD was released for the Mega-CD, a special addon for the Mega Drive, becoming a commercial success and receiving very positive reception. It was later ported to Microsoft Windows in CD-ROM format in 1996, becoming the first Sonic title to be officially available on PC. It introduced the soon-to-be recurring characters Amy Rose, Sonic's self-proclaimed girlfriend who would later become one of the hedgehog's best friends, and Metal Sonic, Sonic's robotic doppelganger created by Dr. Robotnik and first true rival.

Sonic the Hedgehog Spinball, the first spin-off title in the series, was released in 1993 for the Mega Drive, Master System, and Game Gear. It largely followed the concept of Sonic bouncing around as the ball on a giant pinball table that had been used in both Sonic the Hedgehog and ''Sonic the Hedgehog 2. ''While it was commercially successful, the game received mixed reception.

Dr. Robotnik's Mean Bean Machine, the second spin-off game in the franchise, released in 1993 for the Mega Drive, Master System, and Game Gear, was one of the few entries in the series in which Sonic did not make any appearance, not even in a cameo. The game, however, was set in the universe of Adventures of Sonic the Hedgehog, the first Sonic TV show, which was produced by DiC Entertainment and featured that cartoon's version of Dr. Eggman, alongside several of his lackeys such as Scratch, Grounder, and Coconuts. The game branched the series into the puzzle genre for the first time, and was a port for Western regions of Japan's Puyo Puyo, receiving positive reception.

SegaSonic the Hedgehog, also released in 1993, was the first installment in the Sonic series to be released in arcade systems, and introduced new characters to the franchise: Mighty the Armadillo and Ray the Flying Squirrel. It distinguished itself from other Sonic games at the time by presenting a isometric, pseudo-3D perspective in comparison to the traditional 2D fast-paced platforming the series was known for. It was well-received by videogame magazines and got positive scores.

Sonic the Hedgehog 3, released in 1994, continued where Sonic the Hedgehog 2 left, and saw Sonic and Tails venture into Angel Island, after hearing unusual activity coming from the place. It introduced another character to the series: Knuckles the Echidna, who, while an enemy to Sonic and Tails in this game, would become one of their best friends later on. During development, Sonic 3 was split in half, having a direct sequel, Sonic & Knuckles, released later that year, which included the leftover content. Both games sold well and received positive feedback from videogame critics. Sonic & Knuckles also included "Lock-on" technology, which allowed the Sonic & Knuckles cartridge to be connected to an older game to the cartridge's pass-through port to unlock bonuses: If connected to Sonic the Hedgehog 3, the game becomes Sonic the Hedgehog 3 & Knuckles, which is what the developers intended to achieve with the standalone Sonic 3 cartridge, while if it is conected to Sonic the Hedgehog 2, Knuckles the Echidna in Sonic the Hedgehog 2 is unlocked, which allows players to select Knuckles as their character in Sonic 2, although Sonic and Tails are removed in this version; connecting the Sonic & Knuckles cartridge to any other Mega Drive cartridge, including the original Sonic the Hedgehog, unlocks a full version of the Blue Sphere Special Stages''. Sonic 3, Sonic & Knuckles, and the complete Sonic 3 & Knuckles would later be ported to Microsoft Windows in 1997 as a compilation named Sonic & Knuckles Collection.''

Knuckles' Chaotix, released in 1995 for the 32X Mega Drive addon, saw Knuckles the Echidna in the role of protagonist instead of the titular character Sonic (who only makes a cameo in the good ending of the game), and introduced the team that would later be known as the Chaotix, including Espio the Chameleon, Vector the Crocodile, and Charmy Bee, alongside Mighty the Armadillo. Due to the platform it was released in, this game featured higher-quality graphics and soundtrack than preceding entries. While it was the best-selling title for the 32X, it is considered a commercial failure and received mixed reviews overall.

Sonic 3D Blast, an isometric, pseudo-3D "2.5D" title, was released for the Mega Drive in 1996. Sega Saturn and Microsoft Windows ports followed to cover the hole of the cancellation of Sonic X-treme. It featured enhanced graphics and a different soundtrack, composed by Richard Jacques. Sonic 3D Blast was developed by Traveler's Tales, although Sonic Team worked on the Special Stages in the Saturn/PC version.

In 1997, a compilation entitled Sonic Jam was released for the Saturn. In addition to containing Sonic the Hedgehog, Sonic the Hedgehog 2, Sonic the Hedgehog 3 and Sonic & Knuckles, it also included a "Sonic World" mode. This allowed the player to control Sonic in a small 3D world similar to Green Hill Zone from the original game; it contained no enemies and was mainly a means of accessing the disc's multimedia features such as BGM's, illustrations and commercials.

Alongside the 16-bit games, during this time there were also several 8-bit entries developed for the Game Gear and Master System exclusive to those platforms, such as Sonic Chaos in 1993, Sonic the Hedgehog Triple Trouble in 1994, and Sonic Blast in 1996/1997, each with varying degrees of success and following a similar formula to their 16-bit counterparts.

Beginning with Sonic Adventure in 1998, Sonic was redesigned by Yuji Uekawa as a fifteen-year-old character, with longer legs and a less spherical body, longer and more drooping spikes, and emerald-green-colored eyes. Further changes to the character's design were made in subsequent games, namely in Sonic the Hedgehog (2006) and Sonic Unleashed, adding visible fur, a more realistic design for a human world, and making him a bit lankier. Spin-off media such as comics and cartoons have featured variations on all these video game designs, with restrictions set by the standardized model sheets..

To create unique Sonic products in various markets, Sega initially developed two major regional backstories for the instruction booklets; the original Japanese version and a localized version for most other regions, which was the version built upon by the Archie Comics, SatAM, and other media. While sometimes the storyline would have minute differences, other times the storyline would be very different. With the launch of the Sega Dreamcast, the series' storyline took a unified approach and this practice diminished.

Although Sonic R was the first 3D Sonic game, the full leap into 3D platforming was made with Sonic Adventure, a launch title for the Sega Dreamcast console. On 7 June 2001 in North America (23 June in Japan and Europe; the 10th anniversary of the US release of Sonic the Hedgehog), Sonic Adventure 2 was launched. Both of the Adventure titles were later ported to the Nintendo GameCube (under the titles of Sonic Adventure DX: Director's Cut and Sonic Adventure 2 Battle) when Sega dropped out of the hardware market. Sonic Adventure DX was also ported to Windows PCs.

The first Sonic game to release simultaneously on multiple consoles, Sonic Heroes, was released on the Nintendo GameCube, PlayStation 2, and Xbox in December 2003 in Japan, with American and European releases following soon after and a PC version during the following November. The platforming was largely similar to that of the Adventure titles, although the player now controlled the lead character in a team of three-themed characters, with the other two following closely behind. The player could switch to a new leader at any time to make use of each character's unique skills. While it was a commercial success, opinions among both reviewers and fans of the Sonic series were mixed.

Shadow the Hedgehog was released in the United States in November 2005. While it was commercially successful, it received mixed reviews from critics such as X-Play, for instance, who had given it a 1 out of 5, making it the lowest-scoring Sonic game reviewed on the show. Other game sites such as IGN and GameSpot similarly panned the game. Nintendo Power and Gametrailers, however, both rated it above 8 out of 10, praising the replay value. Controversies revolving around this game included the gun play and the over-use of minor profanity and the fact that Sega had decided to switch to the 4Kids Entertainment voice actors from the English version of Sonic X.

A highly faithful two-part port of Sonic the Hedgehog made for mobile phones has been a huge hit in Europe, introducing the game to a new generation of preteen gamers, with respected handheld specialist Pocket Gamer awarding Sonic the Hedgehog Part Two a 9 out of 10 review score.

Other gameplay styles
The Sonic series has also seen installments in another genres and gameplay styles aside the standard platforming it's known for. The first of these was Sonic the Hedgehog Spinball (released on the Mega Drive in 1993 and on the Master System and Game Gear in 1994). The concept of Sonic bouncing around as the ball on a giant pinball table had been used in both Sonic the Hedgehog and Sonic the Hedgehog 2; Sonic the Hedgehog Spinball was designed around that premise.

Several racing games starring Sonic characters have been developed. In Sonic Drift and Sonic Drift 2, characters drive go-karts (kart circuits were later included in the two Sonic Adventure games). In Sonic R (1998), most characters ran on foot (with Eggman riding his Eggmobile and Amy driving a car), while in the Sonic Riders series (2006), they race on hoverboards known as "Extreme Gears." With games such as Sonic & Sega All-Stars Racing, Sonic characters returned to racing in vehicles, alongside other Sega characters.

Sonic Shuffle was a virtual board game/party game for the Dreamcast. Edutainment video games starring Sonic and Tails have also been released, such as Sonic the Hedgehog's Gameworld and Tails and the Music Maker for the Sega Pico, and the PC title Sonic's Schoolhouse.

A fighting game named Sonic the Fighters existed as an arcade game, and later a fighting / platform game hybrid called Sonic Battle was released for the Game Boy Advance.

In 1993, Dr. Robotnik's Mean Bean Machine was released for the Sega Mega Drive. The game was a clone of the Japanese puzzle game Puyo Puyo. This game was also ported to the Game Gear.

In 2008, Sonic Unleashed was released, which brought on a new to the series style of brawling-based combat mixed with platforming in the form of Night stages, played as Sonic the Werehog.

Sonic Chronicles: The Dark Brotherhood brought Sonic into the genre of role-playing games (RPGs) for the first time, mixing turn-based strategic combat and storytelling with traditional Sonic elements.

Giant Rings
A variety of the normal Rings, the Giant Rings are hidden in the games' stages and designed to be jumped through, which would transport the character to a Special Stage, where the character could collect one of the Chaos Emeralds or, in certain circumstances, Super Emeralds. They were used for this purpose in Sonic the Hedgehog, Sonic the Hedgehog CD and Sonic the Hedgehog 3 & Knuckles. Sonic the Hedgehog 2 used the Star Posts instead. In Sonic the Hedgehog 3 & Knuckles, if all the Emeralds had already been found, these Rings could be collected as a normal one, granting 50 normal Rings each, allowing the characters to tap into the power of the Chaos Emeralds (usually becoming Super, or Hyper in Sonic the Hedgehog 3 & Knuckles if the player has collected all the Super Emeralds as well). Since Sonic Adventure 2, they have taken the place of the old Goal Plates as the end level marker and touching it would end the stage.

Shuttle loops
Shuttle loops are circular loop-de-loops of unknown origin that the player runs through as part of the main path during a stage. While the player will often be required to input quick acceleration to get through them in the 2D games, this is often not the case in 3D installments, as the character will usually be launched into them with a set speed once they get near the structure, generally not allowing to backtrack the level.

Chaos Emeralds


The Chaos Emeralds are seven emeralds with mystical powers which are a recurring feature in Sonic games. They are the basic in most of the games' plots, and the player is frequently required to collect them all to fully defeat Dr. Eggman and achieve the games' "good endings", Super forms, or both. The method used to acquire the Emeralds differs between titles in the series. Most early games require the player to find them in Special Stages. In some games, such as Sonic R and the 8-bit versions of Sonic the Hedgehog and Sonic the Hedgehog 2, they can be found in hidden locations within the main levels. In later games, the Chaos Emeralds are found by the characters throughout the games' story modes and do not need to be "found" by the player.

A counterpart to the Chaos Emeralds, known as the Sol Emeralds, appear in the Sonic Rush series.

Master Emerald
The Master Emerald resides in a shrine on Angel Island and is guarded by Knuckles the Echidna; it contains an infinite amount of power, much greater than the seven Chaos Emeralds, and is used to keep the Angel Island afloat in the sky. The Emerald also has the power to fully control everything that the Chaos Emeralds do, including the ability to negate the energy of the Chaos Emeralds, as seen in Sonic Adventure and Sonic Adventure 2, or empower them, as seen in Sonic the Hedgehog 3 & Knuckles. The Master Emerald can also be used to power mechanical devices, and has been coveted by Dr. Robotnik since his discovery of it. During Knuckles' final boss fight in Sonic the Hedgehog 3 &amp; Knuckles, Mecha Sonic powers up using the Master Emerald into a Super State. In earlier materials, the Master Emerald was sometimes called an eighth Chaos Emerald, but this association has been lessened in later games, making it a separate but related entity.

While it was featured prominently in earlier games, more recent entries have diminished the number of appearances of the Master Emerald.

Special Stages
Usually, a Chaos Emerald may be earned in a Special Stage or Special Zone. Special Stages usually take place in surreal environments and features alternate gameplay mechanics to the standard platforming of the main levels: the 16-bit Sonic the Hedgehog  consisted of a giant rotating maze (which many considered a major technical achievement); Sonic the Hedgehog 2, Sonic 3D Blast, Sonic Heroes and Sonic Rush featured "in your face" segments with the hedgehog running along a long tunnel, with a variant of this used for Knuckles' Chaotix, Sonic Advance, and Sonic Advance 3; 3D "collect items" levels, as in Sonic the Hedgehog 3 &amp; Knuckles, which used the same perspective but had Sonic collecting all the blue-colored orbs on the surface of a giant sphere and a different version, the 3D ring-collecting Special Stage, used in Sonic Advance 2. Sonic Chaos (Sonic & Tails in Japan) utilized a variety of gimmicks for its levels.

Some games include Special Stages, but not as a means of collecting Chaos Emeralds. As the Emeralds of the 8-bit version of Sonic the Hedgehog were hidden in the main stages, the game's spring-filled Special Stages were used to obtain 1-Ups and Continues. Similarly, Sonic the Hedgehog 3 &amp; Knuckles, in addition to their main Special Stages, featured entirely optional Bonus Stages, one of which combined the rotating maze of the 16-bit Sonic the Hedgehog with the pinball gambling of Sonic the Hedgehog 2, and Sonic Heroes had an alternate Special Stage for earning lots of extra lives, very much like the one in which Chaos Emeralds are collected, but with the objective being to get to the Goal Ring before time ran out, rather than catching up to the Chaos Emerald at the end of the tunnel.

Just as the design of the Special Stages has changed, so has the means of accessing them. In Sonic the Hedgehog 3 & Knuckles, Giant Rings were hidden in levels to take the player to the Stages, but most other titles involve the collection of a certain number of rings, usually fifty. In both the 8 and 16-bit versions of Sonic the Hedgehog, they were reached by finishing a level with more than fifty Rings; the player would then have to jump inside the giant ring that would appear just after the goal post. In the 16-bit Sonic the Hedgehog 2, reaching a Star Post when they held this number would create a warp of stars which would take a player to the Special Stage when jumped through. Sonic 3D Blast required the player to deliver rings to Knuckles and Tails, who could be found within each level. Sonic Chaos changed the figure, with access to a Special Stage being the reward for collecting a hundred rings, although only when playing as Sonic.

Super transformation
Since the 16-bit version of Sonic the Hedgehog 2, Sonic has had the ability to transform into the faster and practically invulnerable Super Sonic once all seven Chaos Emeralds are collected. After that, Super Sonic can be used in any of the following levels once fifty rings have been collected, although one ring is lost for every second Sonic remains in this form.

In the Sonic Adventure titles, the Special Stages were omitted entirely and Chaos Emeralds were collected in non-interactive cutscenes as part of the story, with Super Sonic only appearing in the climactic final boss fight. This dismayed many fans, who appreciated the additional replay value offered by retrying a game's levels with Super Sonic's additional abilities. Despite several games since returning to the emerald-collecting of the 2D platform titles (including the Advance series, Heroes, and Rush), Super Sonic was again only playable at the end of the game.

However, Sonic Colors and Sonic Lost World returned the ability to access a super transformation in normal levels. They were also some of the few recent games to omit a Super transformation from the final boss battle.

Other characters have also been able to utilize the super transformation. In Sonic & Knuckles, Knuckles the Echidna could also transform into Super Knuckles. By locking-on Sonic & Knuckles to Sonic the Hedgehog 3, Hyper Sonic, Super Tails and Hyper Knuckles also become available, by collecting all seven Super Emeralds in addition to the seven Chaos Emeralds. In Sonic Adventure 2, Super Shadow also appeared at the end of the Last Story, who fought alongside Super Sonic to destroy the Biolizard. In Sonic Rush and Sonic Rush Adventure, Burning Blaze appears for the extra boss, similar to the end of Sonic Adventure 2. She uses the term "Burning" instead of "Super" as she uses the Sol Emeralds instead of the Chaos Emeralds. In Sonic the Hedgehog (2006), Super Silver appears along with Super Sonic and Super Shadow.

A feature unique to Sonic is his ability to use super transformations using different sources of power other than the Chaos Emeralds, each with its own unique abilities. For Sonic and the Secret Rings, Sonic used the World Rings to become Darkspine Sonic. In Sonic Unleashed, Sonic had the ability to turn into Sonic the Werehog from the power of Dark Gaia. In Sonic and the Black Knight, Sonic transforms into Excalibur Sonic using the power of the sacred swords.

Sky, Space and Water
Many games feature or focus on sky and water on their title screens and many later stages are set in either in the sky or space, with many first stages having a heavy focus on water as either an obstacle or in the background.

Characters
Since Sonic's first appearance in 1991, many more characters have appeared and most of them have been added to themain cast. Many of these characters have garnered steady fanbases since their inclusion into the franchise, while other longtime fans have criticized them for allegedly taking the gameplay focus off Sonic:

Music
The music of the Sonic series is considered one of the aspects that make the series popular. Sonic games have featured tunes composed by a variety of people; Masato Nakamura of J-pop band Dreams Come True was responsible for the music of the first two 16-bit games. Ys/Streets of Rage composer Yuzo Koshiro composed the music for the first 8-bit title, barring what was taken from the 16-bit title. Sega's in-house music company, Wavemaster, did the majority of the music in later titles. One Wave Master employee, Jun Senoue, is part of the band Crush 40, and through his ties to the band they have played the main theme tunes of the two Sonic Adventure games, Sonic Heroes, and Shadow the Hedgehog. Heroes and Shadow the Hedgehog also featured other bands, such as Julien-K. Richard Jacques, a frequent composer of music for Sega's games, contributed to the soundtracks of Sonic R and the Saturn/PC version of Sonic 3D Blast.

Notable games
Here is a list of the most notable Sonic games since the series' debut in 1991.

Spin-offs
The Sonic video game franchise has led to a large number of spin-offs in other media, such as TV shows, films and comic series, starring Sonic. Each spin-off incorporates aspects from the games to varying degrees. With few exceptions, each production takes place in their own fictional universe, independent of the video games.

Sonic the Hedgehog (DiC/Cookie Jar/DHX franchise)
Three of western animated TV series based on Sonic are all produced by DiC Productions (now called DHX Media) with a collaboration with Sega of America, from 1993 to 1999.

Adventures of Sonic the Hedgehog (or AoStH for short) is an American animated television series that was first broadcast in September 1993 and has been running in cartoon syndication ever since. It follows the escapades of Sonic and Tails as they stop the evil Dr. Ivo Robotnik and his array of vicious robots from taking over the planet Mobius. The plots very loosely followed the storyline of the video games series; at the time the Sonic games were still quite new and lacking much plot or character development, which was in turn filled in by the show's writers.

The animated television series simply called Sonic the Hedgehog originally aired from September 1993 to June 1995. While Adventures of Sonic the Hedgehog is known for its bright colors and whimsical humor, Sonic the Hedgehog featured darker stories which constituted a departure from the tone of the Sonic games of the time. To distinguish between the two series, fans typically refer to this series as SatAM because it was a Saturday morning cartoon while Adventures of Sonic the Hedgehog aired on weekdays in syndication and using the show's full title would cause confusion in many situations because the show's title is the same as the character's name.

DiC's last Sonic cartoon Sonic Underground ran for only one season, 1998 to 1999; it bears little relation to other entries featuring Sonic (including previous games, comics and the other animated series) and shares few established characters. 65 episodes were originally produced and of those, only forty were released. Unlike its predecessor, SatAM, the heroes do not remain in a sanctuary-like refuge but instead travel around Mobius to battle Robotnik's forces on a global scale. The Mobian civilization featured in the series includes multiple cities, a poor underclass and an aristocracy for the heroes to interact with. Sonic Underground is the only animated series based on Sonic where Tails has not made an appearance.

Other versions
Other Sonic the Hedgehog animation adaptations which are made by other animation studios.

A two-episode OVA film series based upon the game Sonic the Hedgehog CD and the video game series as a whole, Sonic the Hedgehog: The Movie was made in Japan in 1996 and released as a dub in North America in 2000. Unlike the games, the film takes place on a world named Planet Freedom that, as with many anime series, appears to be a crossbreed of a fairytale land and Earth. At the time of its creation, the anime did not differ as far from official canon as it does today; at this point, it could be considered to take place in an a different continuity than the games, just like other versions of Sonic from other media.

The anime series Sonic X is the longest-running and most successful animated series based on Sonic to date. Originally planned as a 52 episode series that would be inspired by the story lines of the Sonic Adventure series, Sonic X has now expanded to 78 episodes with the latest 26 episodes set primarily in outer space. Sonic X is also the only animated series to include Super Sonic. The main difference that sets this series from the other continuities is that Sonic and his friends originally came from an unnamed planet that is in parallel dimensions with Earth.

The CGI animated television series titled Sonic Boom features a comedic take on Sonic and his friends and their never-ending battles with Dr. Eggman as the main media of the Sonic Boom sub-franchise. More than one hundred episodes with a duration of eleven minutes each have aired.

A Sonic the Hedgehog CGI/Live Action film is in development by Sony.

Archie's Sonic the Hedgehog
Sonic the Hedgehog was an ongoing series of American comic books published by Archie Comics. All of Archie's Sonic-related series, miniseries and specials take place in the same fictional universe. This universe features a mixture of characters, settings and situations from the video games, the SatAM cartoon, the various other incarnations of Sonic, and many elements unique to the comic universe. The current status quo of the comic deals with a full-scale war between the Eggman Empire, ruled by Dr. Eggman, and the Freedom Fighters. However, it also features a variety of other villains and heroic characters whom Sonic and the other Sega characters interact with. The comics were cancelled in 2017.

Sonic X was a comic book series that is based on the anime series of the same name published by Archie Comics. It began in September 2005 and was originally meant to be a four-part series; due to the positive reaction to the series' announcement, it was extended to ongoing status before the first issue premiered. The comic is unique in that it is not directly based on the games; the comic is based on the television show and takes place in its expanded fictional universe. The comic borrows elements from the series first two seasons of the show, including Eggman's fortress, (which was destroyed in the first season of the series) and characters from the storyline of Sonic Adventure.

Sonic Universe was a spin-off comic book series published by Archie Comics to the main Sonic the Hedgehog comic series. It mainly featured characters that are less prominent in the main series but the two comic series frequently tied-in with each other.

Sonic Boom was an on-going comic book series for the Sonic Boom sub-franchise published by Archie Comics, taking the main comedic traits of the characters that the series has shown so far.

IDW's Sonic the Hedgehog
The Sonic the Hedgehog comic series began their publishing by IDW Publishing on 4 April 2018. The announcement for the new comic series was made shortly after the termination of the Archie Comics partnership.

Non-Archie/IDW Sonic the Hedgehog comics
The Sonic the Hedgehog manga series, published in Shogakukan's Shogaku Yonensei (literally "fourth-year student") was written by Kenji Terada and it was illustrated by Sango Norimoto. The manga, which started in 1992, was about a hedgehog boy named Nicky who can turn into Sonic the Hedgehog. Sonic fights Dr. Robotnik, with Tails tagging along to help him.

Sonic the Comic, known to its many readers as STC, was a UK children's comic published by Fleetway Editions between 1993 and 2002. Although it was the UK's official Sega comic, Sonic the Comic established its identity and ongoing storyline and setting when Sonic, Tails and their friends were sent forward in time six months. During their absence, Doctor Robotnik successfully conquered the entire planet of Mobius, and Sonic's group were forced underground, operating as "freedom fighters" attempting to bring down Robotnik's rule of the planet. Due to an aggressive series of budget cuts on the part of Fleetway, the series went into full reprint by issue 184; the final story ended with a number of loose ends left untied. An online fan based comic, called STC-Online, has been set up to continue the STC story starting from where the original STC story left off and beginning with issue 224, due to STC being reprints from issues 185 to 223. It has received positive feedback from both fans and writers of the original STC.

Reception
The Sonic the Hedgehog series became an instant success throughout the videogame industry. It leads as a legendary icon throughout the first game, hitting a mega-sensation and becoming the most popular game franchise at that time. Sale estimates for the Sonic series range from 80 to 100+ million copies sold through the span of its history, becoming a best-selling videogame franchise; this figure amounts to a total of 350 million when counting mobile downloads and purchases. The original Sonic the Hedgehog, released in 1991, is also one of the best-selling videogames in history.

The series has won several awards as well. It won "Outstanding Contribution" by the Golden Joystick, the first ever to win that prize. It got Walk of Game, has one several graphic, gameplay, game of the year, and sound awards almost per game. The Sonic the Hedgehog franchise was awarded seven records by Guinness World Records in Guinness World Records: Gamer's Edition 2008. The records include "Best Selling Game on Sega Systems", "Longest Running Comic Based on a Video Game" and "Best Selling Retro Game Compilation" (for Sonic Mega Collection). In the Guinness World Records: Gamer's Edition 2010, the Sonic the Hedgehog series was listed number 15 out of the top 50 video game franchises. In December 2006, IGN ranked Sonic the Hedgehog as the 19th greatest series of all time, claiming that "although recent 3D entries in the series have been somewhat lacking, there is no denying the power of this franchise."

Besides this praise, the Sonic the Hedgehog series has attracted criticism, specially in recent years. Controversy also hits the "annoying" fanbase claimed by several people. A common criticism has been that the variant gameplay styles found in recent 3D titles have strayed from the formula of the original series. Specifically, the series' jump to 3D has been noted as a declining point. In late 2010, Sega delisted several below average Sonic titles, such as the poorly received Sonic the Hedgehog (2006), in order to increase the value of the Sonic brand after positive reception for games such as Sonic the Hedgehog 4 and Sonic Colors. The title Sonic Free Riders won Sh**tiest game of the Year by ScrewAttack and listed Series that should Die by Yahoo! "experts". GameTrailers named it first as Worst Blockbuster Franchise ever. People claim that "Sega’s speedy mascot has had a hard time recapturing the form that put him on top of the gaming world in 1991." Many of these journalistic reviews, however, have been critically panned as well.

Despite some of its more scathing contenders, the Sonic the Hedgehog series still maintains a global position in the gaming world, continuing selling well, and with a very supportive fanbase that has continued to run strong up to this day.

Trivia

 * According to Kevin Eva, the former Sega Europe community manager, the canon and continuity of the Sonic the Hedgehog games are somewhat in flux all the time. As such, certain plot elements are only valid whenever Sega wants or need them to be at the time, and can easily be changed later on.

Notes and references

 * In addition to information taken from the Sonic the Hedgehog games themselves, the instruction booklets of the US and Japanese versions of the games were also used as references for this article.