Sonic the Hedgehog 2 (ソニック・ザ・ヘッジホッグ２ Sonikku za Hejjihoggu Tsū?) is a platform game in the Sonic the Hedgehog series, developed by Sonic Team in collaboration with Sega Technical Institute, and published by Sega for the Sega Mega Drive. It was released in Japan on 21 November 1992 and in North America and Europe on 24 November 1992. It is the sequel to Sonic the Hedgehog and was directly followed by Sonic the Hedgehog 3 in 1994.
In Sonic the Hedgehog 2, Sonic and his new sidekick Miles "Tails" Prower have found out that Dr. Robotnik is attempting to obtain the Chaos Emeralds on West Side Island to power his Death Egg. Sonic and Tails must defeat Robotnik's Badnik army and free their animal friends while racing to stop the doctor's deadly weapon.
Six months after its release, it had sold around six million copies and became the second best selling game on the Mega Drive. It was compatible with the lock-on feature of Sonic & Knuckles which allowed the player to play Knuckles the Echidna in Sonic the Hedgehog 2. The game has been included in a number of compilations on a range of platforms. On 11 June 2007, the game was made available on the Wii's Virtual Console, Xbox 360's Xbox Live Arcade on 12 September 2007 and the PlayStation 3's PlayStation Network on 19 April 2011.
While out looking for new adventures in his personal plane, the Tornado, Sonic the Hedgehog discovers West Side Island, a small island with a pleasant meadow. Landing on the island to relax, Sonic slides his Tornado into the shadow of West Side Island, drawing a white arc with exhaust smoke. However, he does not pay attention to the fact that a certain metallic flying object has been chasing him and suspiciously lands on the other side of the island.
It is said that a very long time ago, the people of West Side Island used mysterious stones to advance their civilization and achieve prosperity. However, when those people tried to use the stones for the wrong reasons, their prosperity vanished overnight. It is also believed that the gods then sealed away the stones within the island's depths.
One day, Sonic notices a shy orange fox tagging behind him, who nervously hides behind a palm tree when Sonic spots him. What Sonic does not notice while he is not looking is that this peculiar fox barely manages to keep up with him. This young fox cub's name is Miles Prower, though he is known as "Tails" due to his two special tails, which has often made him the target of bullying. However, something changed in Tails when he saw Sonic come to the island, and he made up his mind that he wanted to be as cool as Sonic. After Sonic starts running, Tails does his best to keep up with him. Realizing that the young fox is harmless, Sonic allows him to hang around while he freely explores the island, not really caring about him.
On an early afternoon, Tails discovers the lone Tornado on the beach. Being a budding fan of machinery and vehicles, he rushes up to take a closer look. As he is admiring its magnificent build however, he notices that Sonic is taking a nap under the Tornado's wing. Realizing that the hedgehog owns the plane, Tails gently retreats to the other side of it so as not to wake him up. Suddenly however, an ominous flash occurs in the direction of the nearby forest, which is then followed by a horrible explosion. The wild fire blows away various debris, which Tails avoids by taking cover underneath the Tornado as he witnessed robots violently excavating the area. This ceaseless activity threatens to blanket the entire island in its destructive flames.
As it turns out, Dr. Robotnik has detected the presence of all the Chaos Emeralds on West Side Island after following Sonic, including the lost seventh one spoken of in the island's legend. He has thus taken the opportunity to kidnap the island's Animals to rebuild his Badnik forces and search for the Chaos Emeralds so he can finish his ultimate weapon - a space fortress known as the Death Egg. Tails, staring blankly at the fire, turns his head to see Sonic, who is glaring at the forest as well. Wasting no time, Sonic rushes into the forest to set things right, with Tails following him. Meanwhile, in the forest, Robotnik's laughter is heard. He loudly gloats with pride that he had been chasing after Sonic to find West Side Island and get the Chaos Emeralds as a part of his world conquest.
Making their way across West Side Island, Sonic and Tails free the many Zones from Robotnik's rule. They also meet the doctor on many occasions, but they always defeat him. Once the island is freed, they take to the skies in the Tornado to reach the doctor's fortress, the Wing Fortress Zone. However, as they are about to arrive at the vessel, the latter shoots the Tornado, forcing Sonic to hop onto the aircraft and continue onward on his own while Tails and the Tornado fall from the sky. Later, in the control room of the ship, Sonic encounters and defeats Robotnik again, forcing the doctor to escape and take off in his space rocket. Just as Robotnik has left though, Tails arrives in a repaired and modified Tornado and gives Sonic a ride that lets him catch up to the space rocket. Sonic proceeds to grabs a hold of the space rocket as it heads into space and arrives on the Death Egg.
Onboard the Death Egg, Sonic meets Mecha Sonic. After destroying his robot copy, Sonic finds Robotnik and chases after him, but the doctor quickly escapes into his final trump card - the Death Egg Robot, prepared to destroy Sonic with it. After a heated battle, Sonic manages to destroy the Death Egg Robot, which triggers a chain-reaction that causes the entire Death Egg to explode.
Back on West Side Island, Tails and some Animals are looking at the sky as they witness the Death Egg explode, dyeing the sky in pure white. As they wait for Sonic's return, Tails gets worried about the hedgehog. Wanting to help, the fox cub jumps into the Tornado and goes to save Sonic. Meanwhile, Sonic barely manages to escape the Death Egg, leaving Robotnik behind and leaving the space station to fall into the atmosphere. From there, the ending of the game will depend on the player's progress:
- If the player has not managed to get all seven Chaos Emeralds, Tails will catch Sonic on the Tornado as he falls down from the sky. With the two heroes onboard the Tornado and some Flickies following them, Sonic and Tails will pose to the camera. After the credits, an in-game version of the logo of Sonic the Hedgehog 2 will be shown.
- If the player is playing as Tails, the ending will be the same, except that the sequence in which Tails goes to save Sonic will be skipped, and Sonic will be piloting the Tornado instead of Tails.
- If the player manages to get all seven Chaos Emeralds, Sonic will use the Emeralds' power to turn into Super Sonic and safely go back to his home planet. His Super State illuminates the sky like a beacon, which allows Tails to find him and fly through the sky with him and some Lockies.
- If the player is playing as Tails, the ending will be the same if the player did not collect all seven Chaos Emeralds.
|Miles "Tails" Prower||Because of his two tails, he was bullied by everyone when he was little and was timid, but meeting Sonic and striving to be like him made Miles's personality bright, energetic and positive.
Sonic doesn't seem to be paying attention to Miles, but he's actually looking at him sideways.
|Doctor Robotnik||Evil genius scientist. He wants the Chaos Emeralds. His life's work is world domination. His rival is Sonic.|
|Tornado||Sonic's beloved plane, the Tornado. At normal speed, the Tornado can only reach 450km/h, but by installing a custom booster engine tuned by Miles, it can fly past the speed of sound despite being a propeller-driven aircraft.|
|Eggman's Mobile||An all-purpose capsule mecha created by Doctor Robotnik. By changing its attachments, it can travel across water, land, air, and even dive underground. He believes that Sonic won't be a threat to him with this piece of scientific power, but...|
Sonic the Hedgehog 2 is a side-scroller 2D platformer video game, which plays identical as the first Sonic the Hedgehog game. The player can play as either Sonic or Tails or both. They can also play as Sonic while Tails is controlled by a second player or an AI. Both characters share the same abilities. The game has eleven Zones, most of which are divided into two Acts.
The main objective of Sonic the Hedgehog 2 is to finish its Acts in less than ten minutes. In these Acts, the player can find many Rings, which serve as their playable character's main method of protection. If a character is hit while having at least one Ring, they will survive with the cost of losing all their Rings. However, if the playable character is hit without having Rings, they will lose a Life, or get a Game Over if they do not have any Lives left.
From the options menu, players can select to either play as Sonic alone, Tails alone or Sonic and Tails. By default, players control Sonic while Tails tags along unhindered. However, a second player may control Tails separately. Should Tails move off-screen, fall off a platform, or die after getting hit from above, he will eventually return. There is minimal difference when playing as Tails instead of Sonic. Tails cannot fly when played as in this game, though he is several pixels smaller than Sonic, meaning he may not have to duck in some instances.
Obtaining all seven Chaos Emeralds by clearing all of the Special Stages will unlock a new feature: Sonic's ability to change into Super Sonic. When Sonic has collected at least fifty Rings and jumps into the air, he will transform into Super Sonic. In this state, Sonic is virtually invincible, although he can still die by drowning, getting crushed, falling into a bottomless pits, or running out of time. His speed, acceleration and jump height are all increased as well. However, his Super Dash Attack is decreased in effectiveness as the initial velocity is decreased rapidly. Super Sonic consumes one Ring per second, and when he has no Rings left or he reaches the end of an Act, he reverts back to his normal state.
|left/right + down||Super Spin Attack|
|down + //||Super Dash Attack|
- Air bubble
- Chaos Emerald
- Star Circle
Gimmicks and obstacles
- Dr. Robotnik
- Egg Drillster (Emerald Hill Zone) (first appearance)
- Egg Poison (Chemical Plant Zone) (first appearance)
- Egg Hammer (Aquatic Ruin Zone) (first appearance)
- Egg Claw (Casino Night Zone) (first appearance)
- Egg Scorcher Mk II (Hill Top Zone) (first appearance)
- Egg Digger (Mystic Cave Zone) (first appearance)
- Eggmarine (Oil Ocean Zone) (first appearance)
- Flying Eggman (Metropolis Zone) (first appearance)
- Barrier Eggman (Wing Fortress Zone) (first appearance)
- Mecha Sonic (Death Egg Zone) (first appearance)
- Death Egg Robot (Death Egg Zone) (first appearance)
- Emerald Hill Zone
- Chemical Plant Zone
- Aquatic Ruin Zone
- Casino Night Zone
- Hill Top Zone
- Mystic Cave Zone
- Oil Ocean Zone
- Metropolis Zone
- Sky Chase Zone
- Wing Fortress Zone
- Death Egg Zone
In Sonic the Hedgehog 2, there are seven Special Stages. When the player has collected at least fifty Rings and hits a Star Post, a red halo of stars will briefly float above it, which they can then jump into to get to a Special Stage.
Special Stages track the player from behind while they runs through a three-dimensional half-pipe course filled with Rings and Bombs. A set amount of Rings must be collected to pass through three checkpoints and eventually obtain a Chaos Emerald. Playing co-operatively with Tails raises some of the Ring targets in the early Special Stages. The order of stages is fixed in rising difficulty, and the player cannot enter the next stage without passing the previous. Whether the player is able to obtain the Emerald or not, Sonic is transported back to the last Star Post he hit in the Zone when the Special Stage is over.
Once returned from a Special Stage, the entire Zone is reset (except the game timer) - the player is without Rings but all the collected monitors, Rings, and badniks reappear. Also, if Sonic activates a Star Post, all the Star Posts before that one will be activated as well, whether or not with fifty Rings in hand. This creates a tactical element to getting the most out of each Zone in terms of opportunities to grab Emeralds. It is possible to collect all seven within Emerald Hill Zone.
2 Player VS
In 2 Player VS mode, two players compete against each other -either as Sonic or Tails - in a split-screen race through three regular zones and one Special Stage. Regular zones include Emerald Hill, Casino Night and Mystic Cave and have different music from their one player counterparts, while the Special Stage remains the same as in single player. In the regular levels, players are ranked in five areas (score, time, rings held at the end of the level, total rings collected, and number of item boxes broken), with the player scoring highest in the most levels winning the round, while in the Special Stage, players compete to obtain the most rings. Once one player finishes one of the regular levels, the other player must finish the zone within 60 seconds or lose a life.
In case of a tie, an additional Special Stage round must be completed. Also, to heighten the stakes, there are two unique items in versus-mode: a Teleporter item that instantly switches positions between players in a zone, and an Eggman item that damages the unlucky player. Furthermore, an optional setting allows that all item boxes in two-player mode are only Teleporters.
While the original Sonic the Hedgehog was designed by Sonic Team in Japan, development duties for Sonic the Hedgehog 2 were handed over to Sega Technical Institute in the United States. However, experienced Japanese Sega members such as Yuji Naka and Hirokazu Yasuhara (the first game's lead programmer and game planner, respectively) were brought in to work alongside the American developers.
A prototype of the game was discovered on a Chinese GeoCities site and has been widely distributed on the Internet, this is widely known as the "Simon Wai prototype", named after the person who found it. Only four levels can be played in "normal" gameplay; the rest (including several incomplete stages) have to be accessed through the level select code. Many are not entirely playable, but can be explored using Debug Mode. The prototype is frequently examined by hackers to determine how Sonic the Hedgehog 2 was developed. It was stated in an interview with Yuji Naka that this prototype was likely from a demonstration cartridge that was stolen at a toy show in New York in 1992. Akinori Nishiyama has also stated that the leak was due to the lack of security at the time.
There was also another prototype version of the game that was shown on two episodes of Nick Arcade, this being a beta even earlier than the Simon Wai prototype. Many stages in this beta had music from Sonic the Hedgehog instead of their usual music, such as Emerald Hill Zone playing Star Light Zone's music instead of its usual music, and Chemical Plant Zone plays Marble Zone's music. The beta also features many elements from Sonic the Hedgehog, such as the infamous spike bug (where if Sonic hits one set of spikes and flies into another set, he dies immediately), and even the entirely of Green Hill Zone, albeit highly glitchy and unplayable.
Due to the popularity of its predecessor, Sonic the Hedgehog 2 already had an established fanbase anticipating its release. The game received critical acclaim upon release and was a best seller in the UK charts for 2 months. As of 2006, the game has sold over 6 million copies, making it the second best-selling game for the Sega Mega Drive, after the original Sonic the Hedgehog. Out of those 6 million worldwide sales, only 400,000 cartridges were sold in Japan.
|Computer and Video Games||94%|
|Electronic Gaming Monthly||35/40|
|Mean Machines Sega||96%|
|Official Nintendo Magazine||94% (Wii)|
|Official Xbox Magazine (US)||9/10 (X360)|
|Sega Force Mega||95%|
Sonic the Hedgehog 2 received wide critical acclaim. Based on magazine reviews from the early 1990s, the game holds an aggregate score of 93% at Defunct Games, with this being based on 10 reviews. Based mostly on retrospective online reviews from the 2000s, the game holds an aggregate score of 88.44% at GameRankings, based on 8 reviews.
Reviewers praised the game for its large levels, colorful graphics and backgrounds, increased cast of characters, enemies, and music. Upon release, Ed Simrad of Electronic Gaming Monthly stated that the "twice as long" play time offers "more enjoyment for the buck" and that as "a 2 player game, there is twice the fun." He praised the "larger and harder" levels and "quite innovative" new moves, concluding that it is "the best all-around game on the market." GamePro stated that it is "tough to follow up a classic, but Sonic the Hedgehog 2 earns top honors." They stated that "the best thing about Sonic the Hedgehog 2 is that it's just plain fun" and concluded that it gives "plenty of fabulous gaming to pass the time." Andy of Game Informer stated that it is "not as easy as the first and has more variation. The addition of the two-player split screen is great." Jaz of Mean Machines Sega described it as "faster, slicker, more colourful, louder, bigger and much, much tougher than the original," concluding that it is "packed with features, has loads of secrets, and rounds it all up with a superlative two-player mode that'll have your friends queuing round the block to play. Brilliant!"
The game has also been well received in retrospective reviews. 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. Critics also enjoyed the faster gameplay the game offered in comparison to its predecessor, as well as its new features. Lucas M. Thomas of IGN praised the new Spin Dash ability, which would prepare Sonic to launch at a faster speed. Thomas also noted that the levels of Sonic the Hedgehog 2 were designed to showcase the character's speed, and was less a "platform-jumping game" than a "platform-running" game, in slight contrast to its predecessor.
The game's main criticisms concern the competitive, split-screen, two-player mode, a new introduction to the series. The game allowed two-player mode in three different zones, these being Emerald Hill, Casino Night and Mystic Cave. While the mode was generally well-received upon release, several reviewers have criticized the mode's noticeable slowdown, prominent flickering, and squashed play area for each player. However, IGN praised the innovation of the new two player mode, 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 two player racing mode as the "only part of the game that can be faulted," citing that the mode and its split screen view "squeezes the graphics, plumps up the characters and slows down the action."
Electronic Gaming Monthly awarded Sonic the Hedgehog 2 as the Best Game of the Year for the Sega Mega Drive, describing it as "the best Genesis cart to come along in a long time!" Game Informer gave Sonic the Hedgehog 2 the Best Action/Adventure Game award, praising it for keeping "the same look and feel of the original Sonic the Hedgehog, while adding a two-player mode, longer levels, new moves, and better animation. Wow!" Electronic Games chose Sonic the Hedgehog 2 as one of the three nominees for their Video Game of the Year award, along with Street Fighter II and NHLPA Hockey '93.
Sonic the Hedgehog 2 has been listed among the best games of all time. In 2000, Game Informer ranked Sonic the Hedgehog 2 number 61 on its "Top 100 Games of All Time" list, calling it "the most challenging and finely polished Sonic the Hedgehog title." They later ranked it the 97th best game of all time in 2009. Mega placed the game at number 36 in their "Top Sega Mega Drive Games of All Time" list in 1994. It has also been listed among the best games of all time by Electronic Gaming Monthly (in 1997 and 2001), GameFAQs (in 2004, 2005, 2009 and 2014), GamingBolt, Guinness World Records (in 2009), NowGamer (in 2010), Retro Gamer (in 2004), and Yahoo! (in 2006).
|Knuckles the Echidna in Sonic the Hedgehog 2||Sega Mega Drive||The result of locking Sonic the Hedgehog 2 on to Sonic & Knuckles.|
|Sonic Compilation||Sega Mega Drive||Released as a bundle with Sonic the Hedgehog and Dr. Robotnik's Mean Bean Machine in 1995.|
|Sonic Jam||Sega Saturn||Released alongside other Sonic Sega Mega Drive games in 1997.|
|Sega Smash Pack 2||PC||Released alongside other Sega Mega Drive games in 2000.|
|Sonic Action 4 Pack||PC||Released as part of Sega Smash Pack 2, alongside Sonic the Hedgehog CD, Sonic & Knuckles Collection, and Sonic R; in 2001.|
|Sonic Mega Collection||Nintendo GameCube||Released alongside other Sega Mega Drive games in 2002.|
|Sonic Mega Collection Plus||PlayStation 2
|Released alongside other Sega Mega Drive and Game Gear games in 2002.|
|Sega Genesis Collection||PlayStation 2
|Released alongside Sonic the Hedgehog and other Sega Mega Drive games in 2006.|
|Sonic Mega Collection Plus / Super Monkey Ball Deluxe 2 in 1 combo pack||Xbox||Released as part of Sonic Mega Collection Plus, alongside Super Monkey Ball Deluxe.|
|Sonic Gems Collection||Nintendo GameCube
|Released as part of the game's Museum mode in 2005.|
|Sega Mega Drive Collection Vol. 2||Play TV Legends||Released alongside five other Sega Mega Drive games in 2005.|
|Super Sonic Gold||Play TV Legends||Released alongside three other Sega Mega Drive games in 2005.|
|Sonic the Hedgehog 2||Mobile||Released as part of the Sonic Cafe service in 2006.|
|N/A||Wii||Available for download on the Wii Virtual Console. On 29 October 2015, it was reported that the port would be taken down on 30 October 2015.|
|N/A||Xbox 360||Re-released as part of the Xbox Live Arcade service.|
|Sega Fun Pack: Sonic Mega Collection Plus & Shadow the Hedgehog||PlayStation 2||Released as part of Sonic Mega Collection Plus, alongside Shadow the Hedgehog, in 2009.|
|Sonic's Ultimate Genesis Collection||PlayStation 3
|Released alongside other Sega Mega Drive and Game Gear games in 2009.|
|Sonic PC Collection||PC||Released as part of Sonic Mega Collection Plus, alongside Sonic Riders, Sonic Heroes and Sonic Adventure DX: Director's Cut; in 2009.|
|Sonic Classic Collection||Nintendo DS||Released alongside other Sonic Sega Mega Drive games in 2010.|
|N/A||iPhone||Released on iPhone devices in 2010.|
|PC||Released in 2010 alongside other Sega console games as part of the PlaySEGA website.|
|Sonic the Hedgehog 2||Mobile||Released in 2013.|
|3D Sonic the Hedgehog 2||Nintendo 3DS||Released in 2015.|
|Sega Ages: Sonic the Hedgehog 2||Nintendo Switch||Re-released on Nintendo Switch as part of the Sega Ages line. Essentially the same as the Nintendo 3DS release sans the 3D feature, but now with Knuckles the Echidna in Sonic the Hedgehog 2.|
|N/A||Nintendo Switch||Available for download on the Nintendo Switch Online service.|
|Sonic Origins||Xbox Series X and Series S
PC (Steam, Epic Games)
|To be released to celebrate the Sonic series' 30th anniversary in 2022.|
- Display Tails' name as Miles: At the title screen press the following in order: Up, Up, Up, Down, Down, Down, Up. This can be done again to revert Miles' name back to Tails. In the Japanese release Miles is the default name and entering the code will change his name to Tails.
- Act select: - At the Options Sound Test, play the following tunes in order: 19, 65, 09, and 17, which makes the Ring sound play, then press Start to return to the intro/title screen. Once there press Start while holding to enter the Act select. During any Act, by pausing the game, press A to return to the Act Select.
- 14 Continues: At the Options Sound Test, play the following tunes in order: 01, 01, 02 and 04, then the select Player Select to start the game with 14 continues. Oddly enough entering this code will cause all sound test options to be overwritten with the music for Oil Ocean Zone.
- Debug Mode: At the Act Select Sound Test, play the following tunes in order: 01, 09, 09, 02, 01, 01, 02, and 04, activating a Ring chime, and unlock Debug Mode. Then highlight any Act and press Start while holding .
- All 7 Chaos Emeralds: At the Act select Sound Test, play the following tunes in order: 04, 01, 02, and 06, which plays Chaos Emerald music, and get all seven Chaos Emeralds.
|All Multiplayer||Play all four multiplayer zones.||5|
|Emerald Hill||Clear the Emerald Hill Zone 1.||5|
|Casino||Get to the Casino Night Zone.||10|
|Conquering Time||Beat the game in under an hour.||10|
|Chaos Emerald||Get one Chaos Emerald.||10|
|Xbox Live Racer (XBLA)
Online Racer (PS3)
|Win 10 versus zones on Xbox Live/PlayStation Network||10|
|Fast Emerald||Beat Emerald Hill Zone 1 in under 35 seconds in single-player or co-op mode.||15|
|Super Sonic||Become Super Sonic.||20|
|Extended Super||Stay in Super Sonic mode for one minute.||20|
|Fast Chemical||Beat Chemical Plant Zone 1 in under 45 seconds.||20|
|Win||Beat the game.||35|
|Chaos Master||Get all the Chaos Emeralds.||40|
It has been stated that the events of Sonic the Hedgehog 2 have taken place in the Sonic the Comic series published by Fleetway Editions. Though no direct adaptation was made, the game was referenced in Sonic the Comic #27, "A Tale of Tails". In fact, the entire comic series picks up after the events of Sonic the Hedgehog 2.
Archie Comics has made an adaptation of Sonic the Hedgehog 2 as part of their "Genesis" storyline, in Sonic the Hedgehog #228-#229. It has also been stated that the events of the game have happen in the Post-Super Genesis Wave timeline. Eventually, an adaptation of the game in this timeline was made in Sonic the Hedgehog #289, as the second part of the "Genesis of a Hero" storyline.
- The English manual, which was released shortly after the Japanese version, simplified the storyline. It implied that the game instead took place on the same island as the previous adventure, and also altered Tails' character so that he had looked up to Sonic ever since he was a cub, showing off imitations of his role model's famous moves in front of the forest animals. Beginning with Sonic Adventure, the original Japanese storyline was adopted worldwide, and the localized storyline was virtually discarded.
- This is the only 2D Sonic game where the player doesn't get a "Try Again" message after completing the game without collecting all Chaos Emeralds.
- In the second trailer for Sonic the Hedgehog 4: Episode I, during the Sonic the Hedgehog 2 section, Sonic's running animation from the Nick Arcade and Simon Wai prototypes is seen instead of the final version.
- The Debug Mode and 14 continues codes correspond to the English release date of this game (01, 09 ,09 ,02 ,01 ,01 ,02, 04 which is 24 November 1992), although the latter doesn't need the year.
- On the cover for the game in versions outside Asia, Robotnik's usual blue glasses appears to be depicted as empty black eyes. This could be the reason why the older Sonic television shows and comics portrayed Robotnik with black and red eyes.
- This is the first Sonic game to feature a multiplayer mode.
- This is the first Sonic game to use the Spin Dash.
- This was the first main series game to have all seven Chaos Emeralds.
- This game was the Sega Mega Drive's bestseller due to the success of its prequel and the fact that the game was packaged with the Sega Genesis.
- In this game, there is a Super Sonic code that allows the player to obtain all Chaos Emeralds when inserting the level select code. This lets the player turn into Super Sonic with at least 50 rings without completing any Special Stages.
- The app icon for the initial iPhone version of Sonic the Hedgehog 2 uses recycled artwork from Sonic Advance 2.
- On the back of the American Sonic the Hedgehog 2 box, the screenshot of Sonic and Tails in the Oil Ocean Zone is actually a pre-release version of this Zone. A switch can be seen on the right side of the screenshot. When pressed, it would release a large ball from the floor and roll right into the ocean (as seen in the Simon Wai prototype). The switch and the ball did not appear in the final version of this Zone but can still be accessed in the Debug Mode in the final version. The screenshot of Aquatic Ruin Zone is also from a prototype version.
- In the U.S. instruction manual of Sonic the Hedgehog 2, page 7 has a screenshot of the title screen from the Beta 4 prototype. On page 9, the screenshot of the Oil Ocean Zone is also in from a prototype. Its background is different from the final version (most notably, the silver silo in the background is on the right side in the screenshot, but it is located on the left side in the final version).
- Interestingly, the sprite of Super Sonic used for the Super and Extended Super achievements is in fact a fan-made Sonic Battle sprite from a sprite sheet made by JoeTE.
- Boss Attack Zone in the 2013 mobile re-release was originally conceived as a complete one-act level called Egg Gauntlet Zone, which would have used new assets (as well as those from Sonic Crackers) to form platforming sections between each boss. Sonic Team did not agree with changing the location, colors or graphic style of the bosses, so Christian Whitehead deleted the Zone in favor of the more direct boss endurance mode.
- Dr. Eggman has a beard in the US/EU box art, even though he doesn't have one in the game.
- Yuji Naka mentioned in an interview that he took the code from the original Sonic the Hedgehog and optimized it before Sonic the Hedgehog 2 started production.
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