Sonic the Hedgehog 2 (ソニック・ザ・ヘッジホッグ２ Sonikku za Hejjihoggu Tsū?) is a platform game developed by Sonic Team in collaboration with Sega Technical Institute, and published by Sega for the Sega Mega Drive/Genesis. 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.
The story follows Sonic the Hedgehog and his new sidekick Miles "Tails" Prower on their mission to prevent the evil Doctor Robotnik from obtaining the Chaos Emeralds 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. The game was compatible with the lock-on feature of Sonic & Knuckles which allowed the player to play as Knuckles in Sonic the Hedgehog 2. It 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 PlayStation 3's PlayStation Network on 19 April 2011.
- 1 Development
- 2 Plot
- 3 Gameplay
- 4 Characters
- 5 Zones
- 6 Other modes
- 7 Reception
- 8 Release
- 9 Cheat codes
- 10 Achievements
- 11 Trivia
- 12 Videos
- 13 References
- 14 External links
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".) 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 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 shown on two episodes of Nick Arcade of 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.
While out looking for new adventures in his personal plane, the Tornado, Sonic the Hedgehog discovers West Side Island. Landing his plane on the island to check it out and relax, Sonic 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 a mysterious stone to advance their civilization and achieve prosperity. However, when those people tried to use the stone for the wrong reasons, their prosperity vanished overnight. It is believed that the gods then sealed away the stone within the island's depths.
One day later, Sonic notices a shy orange fox tagging behind him, who nervously scurries back into the welcoming shade of the still palm trees 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. Realizing that the young fox is harmless, Sonic allows him to hang around while he freely explores the island.
On an early afternoon, Tails discovered the lone Tornado stranded at the beach. Being a budding fan of machinery and vehicles, he rushes up to take a closer inspection. As Tails is admiring its magnificent build, however he notices that Sonic is taking a nap under the Tornado's wing. Realizing that Sonic 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 finish his ultimate weapon—a space fortress known as the Death Egg. Robotnik now rules the factories, refineries and cities on the island. He has grabbed control of everything except the seven Chaos Emeralds. Wasting no time, Sonic rushes into the forest to set things right, with Tails following him.
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. Eventually, 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 ship, the Wing Fortress Zone uses its lasers to damage the Tornado, making Sonic hop onto the aircraft and continue his adventure on his own. Later, in the control room of the ship, Sonic destroys the Barrier Eggman mechanism controlled by Robotnik himself. His device destroyed, Robotnik escapes and takes off in his Egg Jet. Just as Robotnik has left though, Tails arrives in a repaired Tornado and gives Sonic a ride that lets him catch up to the Egg Jet. Sonic then grabs a hold of the Egg Jet as it heads into space and arrives at the Death Egg.
Onboard the Death Egg, Sonic meets Mecha Sonic, and briefly battles it. After destroying his robot copy, Sonic tries to catch Robotnik, but the doctor quickly escapes into his Death Egg Robot, prepared to destroy Sonic with it. Despite the odds though, Sonic manages to destroy the Death Egg Robot, which triggers a chain-reaction that causes the entire Death Egg to explode. This prompts Sonic to leave space fortress by jumping into space and fall down to the planet. From there, the ending of the game will depend on the player's progress:
- If the player has not managed to get all the Chaos Emeralds, Tails will decide to take off in the Tornado to save Sonic after seeing the Death Egg explode in the sky from the ground. While in the sky, Tails catches 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, Dr. Robotnik is shown laughing while holding the Chaos Emeralds the player did not collect in his hands.
- 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 the seven Chaos Emeralds, Tails will decide to take off in the Tornado to save Sonic after seeing the Death Egg explode in the sky from the ground. As Tails flies through the sky while accompanied by Flickies, Sonic, who has transformed into Super Sonic, will appear and fly along with Tails and the Flickies. After the credits, an infuriated Robotnik is shown jumping on top of an "END" text in frustration.
- If the player is playing as Tails, the ending will be the same as the bad ending. After the credits, an infuriated Robotnik is shown jumping on top of an "END" text in frustration.
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, both of whom have the same abilities. They can also play as Sonic while Tails is controlled by a second player or an AI. 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, falls off in the void, or dies after getting hit 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 Spin 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.
|/ /||Spin Jump|
|left/right + down||Super Spin Attack|
|down + / /||Super Dash Attack|
- Dr. Robotnik
- Egg Mobile-D (Emerald Hill Zone) (first appearance)
- Water Eggman (Chemical Plant Zone) (first appearance)
- Hammer Eggman (Aquatic Ruin Zone) (first appearance)
- Catcher Eggman (Casino Night Zone) (first appearance)
- Submarine Eggman (Hill Top Zone) (first appearance)
- Drill Eggman II (Mystic Cave Zone) (first appearance)
- Submarine Eggman II (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 7 Special Stages. When Sonic has collected at least 50 rings and he hits a Star Post, a red halo of stars will briefly float above it, which Sonic can then jump through to get to a special stage.
Special Stages track Sonic from behind while he 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 the emerald itself. Playing co-operatively with Tails (as seen in the screenshot) raised some of the ring targets in the early stages, for example at the beginning of the first stage 40 rings were required to pass rather than 30. The order of stages is fixed in rising difficulty, and Sonic cannot enter the next stage without passing the previous (unlike Sonic the Hedgehog). Whether the player is able to obtain the emerald or not, Sonic is transported back to the last lamp post he hit in the zone when the special stage is over and has zero rings.
On return from a Special Stage, the entire zone is reset (except the game timer) - the player is without rings but all the collected item boxes and rings reappear (although unfortunately so do the Badniks). Also, if Sonic activates a Star Post, all the Star Posts before that one will be activated as well, whether or not with 50 rings in hand. This created 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, provided the player is careful with the order in which Star Posts are activated (and indeed, very skilled at the Special Stages).
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 a Robotnik item that damages the unlucky player. Furthermore, an optional setting allows that all item boxes in two-player mode are only Teleporters.
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 Genesis/Mega Drive (after the original Sonic the Hedgehog). Out of those 6 million worldwide sales, only 400,000 cartridges were sold in Japan.
|Defunct Games||93% |
|Sonic Retro||93% |
|Computer and Video Games||94%|
|Electronic Gaming Monthly||35/40|
|Game Informer||27.25/30 |
|Official Nintendo Magazine||94% (Wii)|
|Official Xbox Magazine||9/10 (X360)|
|Mean Machines Sega||96%|
|Sega Force Mega||95%|
The game received wide critical acclaim. Based on magazine reviews from the early 1990s, the game has an aggregate score of 93% at both Defunct Games based on 10 reviews and Sonic Retro based on 22 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 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 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 (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, Lucas Thomas 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 it as the best Sega Genesis game of 1992, 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 #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, NowGamer, Retro Gamer and Yahoo!
The game was released in Japan for the Sega Mega Drive on 20 November 1992. The Sega Genesis release in the United States and the European Mega Drive release came later on 24 November, a Tuesday and the release day was dubbed "Sonic 2's Day". Sega claims that they sold 400,000 copies of Sonic the Hedgehog 2 in the first five days after release. It has since been re-released numerous times.
Sonic the Hedgehog 2 with Sonic & Knuckles
Knuckles the Echidna in Sonic the Hedgehog 2 is a game activated by locking Sonic the Hedgehog 2 to the pass-through cartridge of Sonic & Knuckles that was released later by Sega. The resulting game is almost identical to Sonic the Hedgehog 2, except that the player plays as Knuckles the Echidna. As Knuckles has abilities and weaknesses that Sonic and Tails do not, the game is an overall different experience. Knuckles can glide in the air and climb walls with ease, which allows him to access areas otherwise unreachable by Sonic and Tails, while his weaker jumping abilities make some situations, such as certain boss fights (particularly the final boss of Death Egg Zone), more difficult.
|Sega Mega Drive (Genesis)||Included in Sonic Classics (Sonic Compilation in Europe) on the Sega Mega Drive (Genesis).|
|Arcade||This was one of the games adapted for release in arcades using MegaPlay and MegaTech technology in 1993.|
|Sega Saturn||Playable on the game Sonic Jam for the Sega Saturn console.|
|PC||Included in Sega Smash Pack 2 for the PC.|
|PC||Available in Sega Smash Pack 2 which is included in Sonic Action 4 Pack for the PC.|
|PlayStation 2 / PSP||Sega Genesis Collection for PlayStation 2 and PlayStation Portable also includes this game.|
|GameCube||Available on Sonic Mega Collection for the GameCube.|
|PlayStation 2 / PC / Xbox||Available on Sonic Mega Collection Plus for the PlayStation 2, PC and Xbox.|
|Xbox||Available in Sonic Mega Collection Plus / Super Monkey Ball Deluxe 2 in 1 combo pack for the Xbox|
|GameCube / PlayStation 2||Sonic Gems Collection allows you to play the final boss of this game in the museum mode. If you beat Death Egg Zone under the time limit, you can continue on to the beginning of the game until your time runs out.|
|Play TV Legends||Sega Mega Drive Collection Vol. 2 is a game console which is part of the Play TV Legends plug-and-play series. It has 6 built in games that can be played when the console is connected to the TV. The title game is Sonic the Hedgehog 2. This was released in Europe and Japan in 2005.|
|Play TV Legends||Included in Super Sonic Gold, a console that has 4 built in games, but no cartridge slot. Released in the US and Europe in 2005|
|Mobile Phone||In 2006, this game was ported as a mobile phone game and offered on the Sonic Cafe in Japan and Sega Mobile services elsewhere.|
|Mobile Phone||There are several different versions of the phone game. The game is split into 2 parts, titled Sonic 2 Dash and Sonic 2 Crash. Depending on the screen size, they are either identical to the Genesis original or lacking various elements (including Tails and bosses).|
|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.|
|Xbox 360/PlayStation 3||Available for download on the Xbox 360's Xbox Live Arcade service and later made available for download on the PlayStation 3's Playstation Network service. Released 11 June 2007 for Xbox 360 and 19 April 2011 for PlayStation 3. On 29 October 2015, it was reported that the XBLA port would be taken down on 30 October 2015.|
|PlayStation 3 / Xbox 360||Included in a compilation disk titled Sonic's Ultimate Genesis Collection for the PlayStation 3 and Xbox 360.|
|PC||Sonic PC Collection is a compilation released in New Zealand and Australia in 2009. This compilation includes Sonic Mega Collection Plus which includes Sonic the Hedgehog 2.|
|Nintendo DS||Included on a Game Card titled Sonic Classic Collection for the Nintendo DS.|
|iPhone||Sonic the Hedgehog 2 was ported to iPhone on 20 April 2010. Like the initial port of the original Sonic the Hedgehog, this port removes the capability of inserting cheat codes.|
|Browser||Available for VIP users to play on the PlaySEGA browser game service in 2010.|
The 2013 remaster by Christian Whitehead was available as an update to the earlier iPhone version and also available for Android devices. The revised version adds similar modernized touch-ups as Whitehead's previous works of Sonic the Hedgehog CD and Sonic the Hedgehog, adding exclusive features such as Knuckles as a playable character, a fully playable Hidden Palace Zone and a boss attack mode.
Announced on April 2015 as part of Sega 3D Classics' third set, 3D Sonic the Hedgehog 2 was released on July 22, 2015 in Japanese Nintendo 3DS eShop. After two other titles in the third set, 3D Sonic the Hedgehog 2 was released on October 8 in North America priced at $5.99. Like the previous 3D Sonic the Hedgehog, the port is part of series of the Mega Drive games re-released with the feature to play in 3D. The port features the option to use save states, change the display and audio settings, along with the new mode titled "Ring Keeper" that allows the player to start each Zone with 10 Rings and only lose half of them during the mode. Beating the game once unlocks "Super Sonic Mode" in which the player starts with 50 Rings and all Chaos Emeralds. The multiplayer mode of this port is utilized with co-op play.
- 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.
- 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 2 Player mode.
- This is the first Sonic game to use the Spin Dash.
- This was the first Sonic game to not first be released in North America, but instead in Japan.
- This was the first main series game to have all seven Chaos Emeralds.
- This game was the Genesis' 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.
- This game is represented in Sonic Generations. Chemical Plant reappears as the second level of the Classic Era in the home version, while Casino Night appears as the second stage in the portable version. A remix of the 2-player results music can be heard while purchasing Skills in the Skill Shop. One of Sonic's wait animations, in which he looks at his wrist and lays on the ground, also returns as one of Classic Sonic's wait animations. Finally, the Death Egg Robot appears as the Gate Boss of the Classic Era in the home version. During the boss fight, a remix of the Death Egg Robot's theme can be heard.
- The app icon for the initial iPhone version of Sonic the Hedgehog 2 uses recycled artwork from Sonic Advance 2.
- Players are awarded with a "Perfect Bonus" of 50,000 if they complete an Act after collecting every ring in the Act and losing none. This is extremely difficult from Chemical Plant Act 2 and onwards, as Acts will have more paths, some of which become unreachable after a certain spot.
- The ending theme of Sonic the Hedgehog (2006), "Sweet Dreams," sounds very similar to the ending theme of this game.
- The music that also plays on the options menu is very similar to the ending theme of Sonic the Hedgehog 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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- GameSpy: Sega's Yuji Naka Talks!. GameSpy. Retrieved on 27 February 2007.
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- Electronic Gaming Monthly, 1998 Video Game Buyer's Guide, page 87
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- GameFan, volume 1, issue 2, December 1992, pages 9 & 14-17
- Game Informer, issue 8 (January/February 1993), pages 56-57
- "Classic Reviews: Sonic the Hedgehog 2". Game Informer 12 (109): 104. May 2002.
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- Bad Influence!, issue 2, pp. 46-47, 1993
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