Sonic the Hedgehog 2

Sonic the Hedgehog 2 (ソニック・ザ・ヘッジホッグ) is a platform game developed and published by Sega for the Sega Genesis console, released worldwide in November 1992. It is the second main entry in the Sonic the Hedgehog series, and introduced Sonic's sidekick, Miles "Tails" Prower, controllable by a second player. In the story, Sonic and Tails must stop series antagonist Dr. Ivo Robotnik from stealing the Chaos Emeralds to power his space station, the Death Egg.

Development of the game began in November 1991. The game was developed by both Japanese and American staff at Sega Technical Institute; art director Tim Skelly designed the appearance of the game's new 3D special stages, which were based on an earlier tech demo created by Yuji Naka. The staff increased the speed of Sonic the Hedgehog 2 in comparison to its predecessor. As with the first installment, the soundtrack was composed by Masato Nakamura.

Sonic the Hedgehog 2 sold over six million copies, making it the second-best-selling Genesis game behind the original Sonic the Hedgehog. It received highly positive reviews from critics, who commended the game's level design and visuals, although its multiplayer mode was criticized. It has been rereleased on various platforms; a remastered version developed using the Retro Engine released on iOS and Android in December 2013. Two direct sequels, Sonic the Hedgehog 3 and Sonic & Knuckles, were released in 1994.

Plot
The game's premise is similar to that of the original Sonic the Hedgehog. Sonic's nemesis, Dr. Ivo Robotnik, is planning world domination through the power of the Chaos Emeralds and an army of robots powered by trapped animals. Specific to this game, he is additionally constructing an armored space station known as the Death Egg (a parody of the Death Star), also for the means of world domination.

The events of the game see Sonic and Tails chasing Robotnik through West Side Island, and eventually up to the Death Egg, pursuing him with Tails' biplane, the Tornado. The plane is damaged after being shot at, but Sonic still manages to infiltrate the Death Egg, alone. Once there, he battles a robotic imposter before taking on Robotnik, who is piloting a giant mech. Sonic manages to defeat the robot and it explodes, damaging the Death Egg and knocking it out of orbit. Sonic falls to the ground and is saved by Tails in the Tornado. If the player has collected all of the Chaos Emeralds, Sonic, in his Super Sonic form, flies alongside it.

Gameplay
Sonic the Hedgehog 2 is a 2D side-scrolling platform game. The game stars Sonic the Hedgehog and his sidekick, Miles "Tails" Prower, who is described as having idolized Sonic as a child and wanting to keep up with him. At the game's start, the player can select to either play as Sonic, Tails, or both. The difference between the two is purely cosmetic; the two both have identical abilities. In the latter mode, players control Sonic while Tails runs along beside him. A second player can join in at any time and control Tails separately. The game takes place over a series of levels, each divided into one, two, or three acts with a boss fight with Robotnik at the end of the last act. Certain levels have features that are unique to them; for example, Emerald Hill has corkscrew-like loops, and Chemical Plant has boost pads that instantly put Sonic at his top speed. The character can jump on enemies to defeat them; the game also introduces a new move, the "spin dash" or "Super Dash Attack", by which the player curls in a ball and spins while stationary, resulting in a speed boost. When the player is attacked by an enemy without rings, is crushed, falls off-screen, or exceeds the act's ten-minute limit, they lose a life and return to the most recently passed checkpoint. Dying with zero lives gives the player a game over.



When the player collects at least 50 rings and passes a checkpoint, they can warp to a "special stage". In these stages, the player runs through a pseudo-3D half-pipe course, collecting rings and dodging bombs. A set amount of rings must be collected to pass through each of three checkpoints and in turn to obtain the emerald itself. If Sonic collides with a bomb, he loses ten rings and is immobilized momentarily. The stages rise in difficulty, and the player cannot enter any stage without passing the previous one. After finishing, the player is transported back to the star post they used to enter the special stage, with their ring-count reset to zero. When all Emeralds have been collected, if the player chose Sonic, he has the ability to turn into Super Sonic, which requires 50 rings or more. Super Sonic is yellow and invincible to enemy attacks, and his speed, acceleration, and jump height are increased as well. However, he loses one ring per second and reverts to being regular Sonic when all of his rings are gone.

The game also has a competitive mode, where two players compete against each other to the finish line, as either Sonic or Tails, in a split-screen race through three of the regular levels and a special stage. After one player finishes one of the regular levels, the other player must finish the zone within 60 seconds, or the level ends instantly. In the regular levels, players are ranked in five areas (score, time, rings held at the end of the level, total rings collected, and the number of item boxes broken). The player with wins in the most number of categories wins the level. In the Special Stage, players compete to obtain the most rings. The mode ends when all stages have been completed, or if a player loses all their lives, in which their opponent will automatically win.

Knuckles the Echidna in Sonic the Hedgehog 2
Sonic & Knuckles was released in 1994, two years after Sonic 2. The Sonic & Knuckles game cartridge features a special "lock-on" port into which the player can insert other Genesis cartridges. Attaching Sonic 2 unlocks Knuckles the Echidna in Sonic the Hedgehog 2, a variation of Sonic 2 whereby the player plays as Knuckles the Echidna, a character introduced in Sonic the Hedgehog 3 and not playable until Sonic & Knuckles. Though the game is largely identical to Sonic the Hedgehog 2, Knuckles is able to glide and climb walls, allowing him access to areas previously inaccessible to Sonic or Tails. However, he cannot jump as high, making some parts of the game, such as certain boss fights, more difficult. In addition, Knuckles restarts with the amount of rings he collected at checkpoints (if he loses a life), the options are unavailable, the special stages have slightly fewer rings required to collect than before (for example, ten rings fewer than in the special stages with Sonic and Tails), and the two-player mode is removed.

Development
Following the release of the original Sonic the Hedgehog, creator Yuji Naka quit Sega due to disagreements over its corporate policies. Mark Cerny, who had recently founded Sega Technical Institute (STI) in the American state of California, met with Naka in Japan and offered him a higher salary and more creative freedom if he joined STI. Naka agreed, and Hirokazu Yasuhara, the lead level designer of Sonic the Hedgehog, also decided to move to STI. Yasuhara had been assigned to help Cerny establish STI in 1990, but the outbreak of the Gulf War delayed his move to the United States by three months, during which he joined Sonic Team and became part of the Sonic project.

Development of Sonic 2 began in November 1991, two months later than Cerny had intended because Sega of America initially felt it was too soon for a sequel. STI handled development of the game; both American and Japanese staff contributed, although, according to team member Tim Skelly,  "Everyone attached to Sonic 2 ultimately worked for Yuji Naka. I think Naka would have been much happier if he was working with an all-Japanese team, but just because of the language barrier and some cultural differences." Skelly designed the appearance of the game's pseudo-3D special stages, based on a tech demo created by Naka. The special stages were created out of pre-rendered 3D polygons, video of which was compressed and halved, both vertically and horizontally, to fit in the game cartridge. Sonic 2 also introduced Sonic's sidekick, a two-tailed fox that could fly named Tails, inspired by Japanese folklore about the kitsune and created by level artist Yasushi Yamaguchi. Sega of America objected to the character's name, Miles Prower (a pun on "miles per hour"), so he was given the nickname Tails as a compromise. Masaharu Yoshii served as the game's director. The staff increased the speed of Sonic the Hedgehog 2 compared to the first game.

Sonic 2 is believed to have been planned to have time travel aspects and was originally developed alongside Sonic CD as the same game, but Sonic CD eventually became its own game over time. A demonstration cartridge of Sonic 2 was stolen at a New York City toy show early in 1992, which was later attributed to a lack of security. The prototype ROM was rediscovered by a fan named Simon Wai on a Chinese website, and features playable sections of two cut levels from the final release of the game: Wood Zone and Hidden Palace Zone. Hidden Palace Zone was in the game from the start, but removed because of a lack of time and capacity.

"The basic idea was about the same as it was in Sonic & Knuckles. You'd encounter the stage through normal play by collecting the emeralds. The idea behind the stage was, "Where do the Chaos Emeralds come from?" That's where Sonic was originally supposed to be granted his Super Sonic powers. We finally were able to use it in S&K, though it wound up being quite different from what we had planned in Sonic 2. But even from Sonic 1 we'd been throwing around those sorts of ideas. Still, when we were running out of time, we looked over things quickly trying to figure out what to dump ... and CHOP went the Hidden Palace. There's simply no way we could have thrown that in by the deadline at the rate we were going."

- Yuji Naka, on the intended purpose of the Hidden Palace stage

Although a level sharing the same name appeared in Sonic & Knuckles, the original version of Hidden Palace was left unfinished until the remastered iOS port was released in December 2013, which features a redesigned version of the level as an optional stage. Sega also provided some magazines with mockup images that showed another scrapped level, the desert-themed Dust Hill Zone, and the stolen 1992 prototype features an unused level slot titled "Genocide City". Naka has also alluded to another scrapped level in the Sonic Jam Official Strategy Guide, explaining why the Metropolis Zone had three parts to it, while every other level only had two: "Due to problems with the story, Act 3 was going to be a different Zone that would only appear once, but since it was cut, we still wanted to have something after Act 2. So that's why there are three acts in this one. We had already finished the map, and it would have been a shame to waste it, so this is what we went with."

Music
Sonic the Hedgehog 2's music, like the previous game, was composed by Masato Nakamura, bassist and lead songwriter of the J-pop band Dreams Come True. The music began early on in development with only concept images for Nakamura's reference, but having a previous game meant he had experience with creating music for the Genesis and began taking a similar approach to the first game. Nakamura treated Sonic the Hedgehog 2 as a film and designed the music around the atmosphere that he felt from the images of the stages. Except for the graphics and some discussion with Sonic Team, Nakamura was given freedom over the music creation which he believes was the reason why he was able to create "such melodic tunes and unusual rhythm patterns".

Nakamura created the music while he was recording with Dreams Come True in London, working on their fifth album The Swinging Star. As a gift to Sonic Team, Masato produced an alternate version of the ending theme with Dreams Come True, which was included in the album they were recording at the time. In 2011, the stage music from Chemical Plant and Casino Night Zone were remixed by Sega for use in Sonic Generations.

Later in October of the same year, a three-disc compilation of the music from Sonic the Hedgehog and Sonic the Hedgehog 2 was released in Japan. Alongside music from the game, the compilation includes comments by Yuji Naka and an interview with Nakamura. The first disc contains original tracks from both games, and the second contains Nakamura's demo recordings produced during the games' development. The third disc contains "Sweet Sweet Sweet" by Dreams Come True, its English-language version "Sweet Dream", and 2006 remixes of both songs by singer Akon which were used in Sonic the Hedgehog (2006).

Release
Sega launched a $10 million advertising campaign for Sonic the Hedgehog 2's release. Sega sought a global release date to make the game available in all stores on the same day, a fairly novel concept at the time. This required Sega to reconfigure its distribution system to ensure that games were available in all major stores. The release date, Tuesday, November 24, 1992 was marketed as "Sonic 2s day". While the Genesis release in North America and the Mega Drive release in Europe both released the game on this day, Sega made the game available a few days before in Japan on November 21, 1992. 400,000 copies of Sonic 2 were sold in the first seven days after release and over 6 million in the lifespan of the console (only 180,000 of which were in Japan ).

8-bit version
A version of the game for the Sega Master System and Game Gear was developed by Aspect. Though based on the original game of the same name, it is a distinct game, with different level designs and a different plot, and this version, unlike the 16-bit release, does not have the spin dash, which led it to being thought to be made before the Sega Genesis version.

2013 remaster
A remastered mobile port was released for iOS, Android, and Windows Phone devices on December 12, 2013. This version was developed from scratch by Christian "Taxman" Whitehead and Simon "Stealth" Thomley using the Retro Engine previously used in the 2011 remaster of Sonic CD. This version adds several enhancements, such as widescreen graphics, Knuckles as a playable character, time and boss attack modes, online multiplayer, additional multiplayer stages, and the previously unreleased Hidden Palace Zone. Additionally, Tails is given his abilities from Sonic the Hedgehog 3, and the remaster features a post-credits scene which depicts the Death Egg crash-landing on Angel Island. This version was received positively, with Shaun Musgrave of TouchArcade declaring it the "definitive version" of the game. The iOS version was updated in 2016, adding compatibility for Apple TV.

Compilation releases
Compilations that include the game are Sonic Compilation (1995) for the Sega Mega Drive/Genesis; Sonic Jam (1997) for the Sega Saturn; Sonic Mega Collection (2002) for the Nintendo GameCube; Sonic Mega Collection Plus (2004) for the PlayStation 2, Xbox, and PC; Sega Genesis Collection (2006) for the PlayStation 2 and PlayStation Portable; Sonic's Ultimate Genesis Collection (2009) for the Xbox 360 and PlayStation 3; and Sonic Classic Collection (2010) for the Nintendo DS.

Download releases
The game was made available for download on Wii's Virtual Console on June 11, 2007, PlayStation 3 via the PlayStation Network on April 19, 2011, and Xbox 360 via Xbox Live Arcade, the latter having enhancements such as online leaderboards, achievements, and online play. Various mobile phone versions exist as well, including the iOS release. The game was released as part of the Nintendo 3DS 3D Classics line in Japan on July 22, 2015, with a release in North America and Europe initially slated for September 2015, before being pushed back to October 8. In 2018, Sega announced a Nintendo Switch port will be released as part of the Sega Ages product line. It will include most of the features added to the 3DS version; it also adds the option to use Sonic's Drop Dash ability from Sonic Mania (2017) and a time attack mode.

Reception
Due to the popularity of its predecessor, Sonic the Hedgehog 2 already had an established fanbase anticipating its release. The game received critical acclaim and was a bestseller in the UK charts for 2 months. As of 2006, the game had sold over 6 million copies, making it the second best-selling game for the Sega Genesis (after the original Sonic the Hedgehog).

Reviewers praised the large levels, colorful graphics and backgrounds, increased characters, enemies, and music. GameSpot stated that "time may have eroded Sega's prominence, but it hasn't done much to diminish how sweet Sonic the Hedgehog 2 is," and, along with other reviewers, commented on how it is still a fun game to play. Electronic Gaming Monthly named it the best Genesis game of 1992. In 2000, Game Informer ranked Sonic 2 number 61 on its "Top 100 Games of All Time" list, calling it "the most challenging and finely polished Sonic the Hedgehog title." Mega placed the game at #36 in their "Top Sega Mega Drive Games of All Time" list. Critics also enjoyed the faster gameplay in comparison to its predecessor, as well as its new features. Lucas Thomas of IGN praised the new "spin dash" ability.

The main criticisms were of the two-player mode, a first for the series. Reviewers criticized the mode's slowdown and flickering, and the squashed play area. However, Lucas Thomas praised the innovation, quipping that "Mario and Luigi could never run competitively through the same levels, at the same time". William Burrill of the Toronto Star described the racing mode as the "only part of the game that can be faulted," as its split-screen view "squeezes the graphics, plumps up the characters and slows down the action."

Legacy
Sonic 2's success was a major factor in Sega catching up to Nintendo in the early-1990s console wars. It brought their market share up to 40% within six months of its release. Tails, whom Sonic the Hedgehog 2 introduced, went on to become one of the most prominent characters in the series, appearing as Sonic's sidekick in most Sonic media, including in recent games such as Sonic Colors, Sonic Generations, and Sonic Lost World. Sonic the Hedgehog 2's popularity extended to various merchandise such as comic books such as Sonic the Comic, a television series, and a sequel, Sonic the Hedgehog 3, which received similar acclaim.

For Sonic's 20th anniversary, Sega released Sonic Generations, which remade aspects of various past games from the franchise. The PlayStation 3, Xbox 360, and PC versions contained a remade "Chemical Plant" level. It also contained a remake of the final boss fight, the Death Egg Robot, as the Classic Era boss of the game. Separately, the Nintendo 3DS version of the game contained a remake of the "Casino Night" level. A "Casino Night" themed pinball minigame was made available for download as a pre-order bonus for the console versions at GameStop. Remade versions of Chemical Plant and Oil Ocean also appear in the 2017 game Sonic Mania.

In 2008, an unofficial, high-definition remake was announced titled Sonic the Hedgehog 2 HD, which included development members who would later work on Sonic Mania. In 2012, it was reported that a potential keylogger was included with an alpha build of the game, which led to the project being discontinued due to the controversy. In 2014, the project was restarted under a new development team. The final version is planned to feature additional stages and the option to play levels as Knuckles the Echidna.