Sonic the Hedgehog CD (ソニック・ザ・ヘッジホッグ ＣＤ Sonikku za Hejjihoggu Shīdī?), more commonly known as Sonic CD (ソニック ＣＤ Sonikku Shīdī?), is a 2D platformer game in the Sonic the Hedgehog series, developed by Sonic Team and published by Sega. It marked the first official appearance of both Metal Sonic and Amy Rose. It was released for the Sega Mega-CD in Japan on 23 September 1993, in Europe in October 1993 and for the Sega CD in North America on 23 November 1993.
- 1 Plot
- 2 Gameplay
- 3 Characters
- 4 Rounds
- 5 Development
- 6 Cast
- 7 Soundtrack
- 8 Reception
- 9 Re-releases
- 10 Cheat codes
- 11 Adaptations
- 12 Trivia
- 13 Videos
- 14 References
- 15 External links
On Sonic's world, there is an enormous lake called Never Lake, which is known for being where the mystical Little Planet, a small planet of both beauty and wonder, appears above for one month once a year. Also known as the "Miracle Planet", Little Planet is known for being the home of the Time Stones, seven mystical gemstones that can freely control time, which allows them to turn a desert into a jungle, clean polluted lakes, and other time-crossing wonders.
Not long after Little Planet makes its annual appearance at Never Lake, Dr. Robotnik takes notice of the Time Stones. Intending to build a fortress on the planet and use the Time Stones for his goal of global domination, Robotnik goes to Never Lake to seize Little Planet for himself. To make sure that Little Planet does not leave, the doctor chains it to a nearby mountain with his face sculpted on it, before covering Little Planet in a metallic shell as he constructs his fortress, all while scouring the planet for the Time Stones. Meanwhile, Robotnik uses the unique temporal passages on Little Planet to invade the past of the planet, where he fills it with robot transporters and Metal Sonic Projectors in order to turn its future into one where he has total control. This affects Little Planet's fate severely, to the point where it becomes a ruined land in Robotnik's future.
Eventually, Sonic the Hedgehog races his way across fields, over lakes and through forests to get to Never Lake and see Little Planet for himself, not knowing about Robotnik's actions. Upon receiving the report that Sonic is approaching, Dr. Robotnik's eyes light up and a fearless smile appears on his face. Assured that he will be able to finally crush Sonic once and for all with his scientific prowess, Robotnik excitedly proclaims, with a blue flash of light that lurks behind him, that he will seize the Time Stones and finally conquer the world.
Meanwhile, Sonic arrives at Never Lake. To his surprise however, he finds Little Planet in its sad and chained state following Robotnik's takeover. Seeing the planet chained to the nearby mountain, he suspects that the doctor is behind it all, and travels to Little Planet via the chain keeping it tied to his world. Ending up in Palmtree Panic, Sonic learns that he needs to destroy the robot teleporters in the past and secure the Time Stones before Robotnik. As he continues his adventure however, he meets Amy Rose, a female hedgehog, who has come to Little Planet after predicting a "destined" encounter with Sonic on the small world with her tarot cards. Upon seeing Sonic, Amy instantly falls in love with him and tries to hug him. Not reciprocating Amy's advances, Sonic tries to continue with his adventure.
After encountering Robotnik and forcing him to retreat by defeating his EGG-HVC-001, Sonic continues onward to Collision Chaos, with Amy following him. Upon arriving there however, Amy is kidnapped by Robotnik's latest and greatest creation to date: Metal Sonic, a lethal robot built in Sonic's image. The robot proceeds to leave with Amy despite Sonic's attempts to save her. Now having to save both Little Planet and Amy, Sonic continues onward across Little Planet, overcoming and defeating Robotnik and his contraptions along the way.
Eventually, Sonic arrives in Stardust Speedway. There, he finds Robotnik and Metal Sonic, who challenge him to a deadly race, with Robotnik keeping a laser active behind them as they race forward. In the end though, Sonic defeats Metal Sonic, who gets smashed after he crashes into a gate closing in front of him, which forces Robotnik to retreat. Afterward, Sonic frees Amy, who hugs him as thanks.
After saving Amy, Sonic travels to Metallic Madness. Inside this stronghold, he eventually encounters Robotnik using the Egg Spinner in an attempt to defeat Sonic. However, the machine is destroyed, triggering a chain reaction that causes Little Planet's metallic shell to crumble and forces Sonic to escape from Little Planet with Amy. Landing near Never Lake, Sonic leaves Amy in a safe place and runs away, before noticing the shell covering Little Planet break apart. After that, the ending of the game will depend on the player's actions:
- If the player has not managed to secure a good future for all the Rounds in the game, Robotnik will retreat on his hovercraft with a blue Time Stone in the palm of his hand while laughing at Sonic. Noticing the doctor, Sonic will throw a rock at him, hitting his vehicle and causing it to explode. A post-credits scene will show Little Planet re-appearing above Never Lake in its poor state once more. The text "TRY AGAIN" will also be shown.
- If the player has managed to secure a good future for all the Rounds in the game, Sonic will look at Little Planet, which will be shaking for a moment before disappearing and leaving behind some sparks in the shape of Sonic's face. After the credits roll, some Little Planet flowers will appear around Never Lake with the text "YOU'RE TOO COOL!" appearing.
|Amy Rose||A cheerful girl full of energy who likes mysterious things and fortune-telling. She came to Little Planet by the "divine message of cards," but there she has a "destined" encounter with Sonic. And then...|
|Dr. Robotnik||An evil genius scientist. This time around, his target is the Time Stones. He also schemes for world domination. In order to oppose his rival, Sonic, he has constructed a robot just like him.|
|Metal Sonic||The ultimate robot built by Robotnik. His abilities are the same as Sonic's, and what's more, he can put out speeds faster than Sonic in an instant. Aligned with Robotnik's intentions, he regards Sonic as an enemy.|
Sonic the Hedgehog CD is a side-scrolling 2D platforming video game which plays similar to past Sonic games. The game is split into seven levels (known as "Rounds"), each divided in three playable acts called "Zones". The playable character here is Sonic, whose most basic actions involve running and jumping. He can also perform the Spin Dash and Super Peel Out.
The main goal of Sonic the Hedgehog CD is to beat each of the Zones in each Round in the game, with the third one of each Round being a boss fight, in less than ten minutes. The Zones are designed so that they branch in numerous different paths, offering the player more secrets to find. To finish the first two Zones, a Goal Plate has to be spun. The third ones on the other hand, require that a Capsule is destroyed.
Throughout the first two Zones of a Round, the player can find Time Warp signs. Their main purpose is to make Sonic enter the Time Warp. If Sonic touches a Time Warp sign and then runs at a set speed for a short period of time, he will enter the Time Warp and end up in another timeframe; touching a "Past" Time Warp sign will send them to the past, while a "Future" one will send them to the future. However, in the past, only the "Future" Time Warp signs are seen, which will send the player back to the present. The same is applied to the future.
The player will start at the present of the first two Zones of a Round, while Zone 3 will always take place in the future. By default, the future will be depicted as a chaotic and ruined place ruled by Dr. Robotnik. However, if the player travels to the past and destroys a robot transporter, they will create a "good future" in that Zone. Getting a good future in the first two Zones of a round will make Zone 3 of it take place in the good future. Furthermore, destroying all robot transporters will result in the good ending of the game being played upon competing it.
In gameplay, Rings appear scattered through the Zones. The number of Rings carried by the player is displayed in the top left corner of the HUD. As with past Sonic games, Rings serve as the playable character's main method of protection from damage; if the playable character takes damage while they carry at least one Ring, they will survive, though they will lose all their Rings. Taking damage while not holding any Rings will cost the player a life. The player can also lose a life if they drown underwater, get crushed, fall into a bottomless pit, or spend ten minutes in the same Zone. After losing a life, the playable character will respawn at the latest Lamppost they touched, or at the start of a Zone if they have not touched any Lamppost or are in any timeline that is not the present. If the player runs out of lives, they will get a Game Over. Extra lives can be obtained by breaking 1-UP Monitors, collecting one-hundred Rings, or every fifty-thousand points collected. Upon obtaining an extra life, a voice saying "Yes!" will be heard.
The secondary objective of Sonic the Hedgehog CD is to gather the seven Time Stones by completing Special Stages. To enter a Special Stage, the player must collect at least fifty Rings in any of the first two Zones of a Round and then enter the Giant Ring at the end of them. Collecting all seven Time Stones will automatically ensure a good future in every Zone of the game.
|Button formation||Character movement|
|Move + down||Spin Attack|
|/ /||Spin Jump|
|Look up + / /||Super Peel Out|
|Duck + / /||Spin Dash|
|START button||Pause the game / Skip the Time Warp animation|
- Air Bubble
- Little Planet flowers (first appearance)
- Metal Sonic Projector (first appearance)
- Robot transporter (first appearance)
- Super Ring (first appearance)
- Time Bonus (first appearance)
- Time Stone (first appearance)
- UFO (first appearance)
Gimmicks and obstacles
- Amy Rose (first appearance)
- Dr. Robotnik
- Metal Sonic (first appearance)
- Miles "Tails" Prower (cameo)
- EGG-HVC-001 (Palmtree Panic) (only appearance)
- Egg Tilter (Collision Chaos) (only appearance)
- Egg Bubble (Tidal Tempest) (only appearance)
- Egg Conveyer (Quartz Quadrant) (only appearance)
- Egg Razer (Wacky Workbench) (only appearance)
- Metal Sonic (Stardust Speedway) (first appearance)
- Egg Spinner (Metallic Madness) (only appearance)
- Palmtree Panic: A tropical level with mountains and waterfalls in the background. The past features a more prehistoric looking Palmtree Panic. The bad future is completely mechanized with smog in the air and oil in the water. The good future is also mechanized, but bright, vivid, colorful, and clean, with potted plants and trees adorning the area as well.
- Collision Chaos: An unusual mechanized forest with an established casino. In the past, Collision Chaos shows a rather surreal, orange tinted forest. The bad future is dark and creepy with gray machines. The good future shows a bright pink and blue futuristic paradise.
- Tidal Tempest: An underwater area at the base of a volcano. In the past, it's an underground cavern, untouched by man or machine. The bad future shows a broken down, polluted, over-industrialized water plant. In the good future, Tidal Tempest is a fully operational turquoise aquarium harboring much plant life and fish. The water level appears to have risen over time: it's low in the past, higher in the present, and at its highest in either future.
- Quartz Quadrant: Quartz Quadrant is a busy place with conveyor belts and platforms. The appearance of this level changes drastically throughout each time Zone. It is a swamp in the past with hardly any technology, but a large quantity of quartz. It's an active mine and partially a swamp in the present. It is an overly mechanized mine with apparently no quartz in the bad future. It is an underground golden-colored city that is possibly made of quartz in the good future.
- Wacky Workbench: A factory level located in a canyon. The past features an early construction of the Workbench. In the bad future, the level is ruined and rusty, while the good future shows an advanced pink/purple plant similar to that of a fictional toy factory.
- Stardust Speedway: One of the fastest Rounds in Sonic history. Stardust Speedway is a highway adorned with musical instruments above an enormous city. In the past, the land is old, ancient, resembling a Roman city, and vines adorn the highway as there is little to no technology to speak of. It also has Gothic-styled buildings in the Zone's center. In the bad future, Stardust Speedway has become a corrupted, polluted dystopian city underneath a large electrical storm with a completed statue of Robotnik in the Zone's center. The good future looks like a giant futuristic amusement park, with bright pink and green colors dominating the landscape with a beautiful cathedral in the center of Zone 2.
- Metallic Madness: Robotnik's base of operations on the Little Planet. The past shows the base still in construction with cranes adorning the skyline, while in the bad future, Metallic Madness is a dark, sinister completely broken-down base ruined from neglect. The good future still shows a mechanized factory, but it has become more in tune with nature, as though Robotnik was never there.
As in the original Sonic the Hedgehog, Special Stages can be accessed at the end of each Zone if the player has collected, and is holding on to, at least fifty Rings. A Giant Ring will then appear above the Goal Plate which the player can jump through to enter the Special Stage.
The Special Stage consists of a three-dimensional, flat surface. To complete a Special Stage and thus collect its Time Stone, the player must seek out and destroy six UFOs flying around the area before time runs out. The UFOs move around in an erratic fashion, which can make them harder to hit. If a UFO is destroyed, it gives a prize: UFOs with yellow frames give a Ring Bonus, and UFOs with white frames give temporary speed boosts. Also, if the timer goes below twenty seconds, a special blue UFO with red frames will appear in the center. This UFO does not count towards the actual UFO count, but it awards the player an extra thirty seconds to complete a Special Stage.
In a Special Stage, there are many gimmicks and obstacles the player can interact with. Springs bounce Sonic upwards; Bumpers bounce Sonic back when touched; Fan Blocks make Sonic float for a short time; Chopper Blocks tiles slow Sonic down and causes him to lose Rings; and Dash Zones force Sonic into different directions. If Sonic steps into the water portions of the stage, ten seconds will be lost from the clock.
After either succeeding or failing to beat the Special Stage, the game will count the obtained points and add them to the player's score. The player will be then sent to the next Zone, where they will resume playing the Zones as normal.
After the release of Sonic the Hedgehog, Lead Programmer Yuji Naka had grown dissatisfied with the rigid corporate policies at Sega, so he moved to the United States to work with the Sega Technical Institute. Incidentally, a large number of the original design team of Sonic also left for the U.S., to help instruct the American developers. With half of Sonic Team and two of its most important creators present, the Sega Technical Institute eventually got the job to develop Sonic the Hedgehog 2.
Meanwhile in Japan, Sonic the Hedgehog CD was handled by a separate development team, headed by Sonic creator Naoto Ohshima. Initially, as revealed in interviews and magazine articles, Sonic the Hedgehog CD, and Sonic the Hedgehog 2 for the Sega Mega Drive, Sega Master System and Sega Game Gear were all supposed to be the same game. However, during development, Sonic the Hedgehog CD evolved into a vastly different type of game. Eventually, the gameplay of Sonic the Hedgehog 2 would be favored for the future games, but this explains why the theme and handling of Sonic the Hedgehog CD are different, as well as the use of Sonic the Hedgehog's sprites for Sonic.
|Sonic the Hedgehog||Masato Nishimura|
The soundtrack of Sonic the Hedgehog CD was composed by Naofumi Hataya. Notably, it was the first Sonic game to have vocal songs, which featured vocals by Keito Utoku. The opening and ending songs were titled "Sonic - You Can Do Anything" and "Cosmic Eternity - Believe in Yourself" respectively.
In North America, the release of Sonic the Hedgehog CD was delayed to have an entirely new soundtrack composed by Spencer Nilsen, who had already composed soundtracks for other Sega CD soundtracks, with the help of David Young. Most of the tracks were replaced with new ones, the exceptions being the "past" tracks. A new song performed by the Nilsen and female band Pastiche named "Sonic Boom" was used for the opening and ending of the game.
This difference in soundtracks, rather infamously, polarized opinions concerning which soundtrack was the better one. Gaming magazine GameFan, which gave the Japanese version a score of 100%, gave the game a less-than-flattering score for the American version and it was made clear that the score had been based on the latter version's soundtrack alone, rather than any changes in the gameplay. In response to the controversy regarding the soundtracks, Spencer Nilsen said that he believed the arguments to be "ridiculous" and that "[both soundtracks] really represent two completely different musical philosophies and approaches". He also thought that "critics were trying to find a reason to bash the game", although he acknowledged that replacing the soundtrack for the game, which was already out for some months, was like "replacing the soundtrack of a Star Wars movie after it had been out for a while".
Both the Japanese and American soundtracks of Sonic the Hedgehog CD were included in various music albums related to the series, and so were they remixed in future releases. Sonic the Hedgehog Boom includes slightly rearranged versions of most of the tracks from the American soundtrack. Sonic the Hedgehog - Remix has original music composed by Naofumi Hataya, which uses samples from the Japanese music of the game. Sonic the Hedgehog CD Original Soundtrack 20th Anniversary Edition, released in 2011, includes all of the tracks from the Japanese soundtrack of Sonic the Hedgehog, as well as remixes of "Stardust Present" and "Sonic Boom" from the American soundtrack by Crush 40 and Cash Cash. In 2019, the Japanese soundtrack was released on the Sonic CD vinyl album. During the Sonic the Hedgehog 30th Anniversary Symphony in 2021, Crush 40 played "Sonic Boom" once again.
|Computer and Video Games||85/100|
|Electronic Gaming Monthly||34/40 (SCD)|
|GameFan||400/400 (MCD) |
|Electronic Games||92% (SCD)|
|Sega Force Mega||85% (MCD)|
Sonic the Hedgehog CD received critical acclaim, with a consensus that it was one of the best games for the platform. The game was praised for its innovative time-travel based gameplay, presentation and music. It became the platform's best-seller. The Android version later sold more than 100,000 paid downloads.
Mega placed Sonic the Hedgehog CD at #3 in their list of the Top 10 Mega-CD Games of All Time. The game was awarded Best Sega CD Game of 1993 by Electronic Gaming Monthly. In May 2009, GamePro listed Sonic the Hedgehog CD as one of the Top 20 Best Platformers: 1989 to 2009, ranking the game in 12th place. GamesRadar listed Sonic the Hedgehog CD as the 68th best game of all time.
|Sonic the Hedgehog CD (Windows 95)||PC||Re-released for Windows 95 devices in 1996.|
|Sonic Gems Collection||Nintendo GameCube, PlayStation 2||Released in a compilation of other Sega Mega Drive and Sega Game Gear games in 2005.|
|Sonic the Hedgehog CD (2011)||Mobile devices, PC, PlayStation 3, Xbox 360||Re-released in 2011 to celebrate the 20th anniversary of the Sonic series. It was released on 14 December 2011.|
- Stage Select: At the title screen, press UP, DOWN, DOWN, LEFT, RIGHT, B.
- View staff's Time Attack records: At the title screen, press RIGHT, RIGHT, UP, UP, DOWN, C.
- Move title screen clouds: At the title screen, hold A and press UP, DOWN, DOWN, DOWN, DOWN, UP. The clouds can then be controlled using the directional pad on the second controller.
- Sound Test: At the title screen, press DOWN, DOWN, DOWN, LEFT, RIGHT, A.
- Edit Mode: At the sound test, select the following then press START: FM40, PCM12, DA11. An image of Tails will also be displayed.
- Secret Special Stage: At the sound test, select the following then press START: FM#07, PCM#07, DA#07.
- Hidden Images: At the sound test, select the following then press START.
|"You are cool"
The Palmtree Panic Good Future theme plays here.
|Parody of Batman.
The final boss theme plays here.
The Metallic Madness Present theme plays here.
|"Infinite fun. Sega Enterprises"
- Mazin Picture
The boss theme plays here.
|Tails and his favorite car, the Lotus Seven. Also enables Edit Mode.
The end credits theme plays here.
Archie Comics later made a tie-in for Sonic the Hedgehog CD in Sonic the Hedgehog #25. It has also been stated that the events of the game have taken place within the In Another Time, In Another Place reality. Sonic the Hedgehog CD would also occur in the Post-Super Genesis Wave timeline, and would be adaptated in Sonic the Hedgehog #290, as the final issue of the Sonic the Hedgehog comic series and the third part of the "Genesis of a Hero" storyline.
- All seven of the game's Rounds have alliterative names.
- In the Sonic Gems Collection version of Sonic the Hedgehog CD, the water in the game is clear. This is because it is a direct port of the Windows 95 version, which utilized a certain graphics card for the water which was not emulated.
- The "Past" background music tracks, which are in PCM format, cannot be played in the D.A. Garden.
- Sonic the Hedgehog CD is the first in the Sonic game series to feature animated cutscenes.
- The animated short that introduces the Mega-CD version of Sonic the Hedgehog CD is substantially shorter than the intro in the PC and Nintendo GameCube ports, as well as the Sega Saturn Sonic Jam video, but animates slower.
- The uncut intro shows more of Sonic running through the landscape and over a lake. Strangely, a very small cut (about two seconds of footage) of the mountainside that Dr. Robotnik uses to tether the little planet down, which has a massive carving of Robotnik's face on it, is missing from the uncut intros but present in the Mega-CD version. There is also a short segment missing from the ending FMV of the Mega-CD version that was restored in Sonic Jam and Sonic Gems Collection. This segment is viewed in its original form at the Pencil Test.
- When accessing the Edit Mode of Sonic the Hedgehog CD, a secret picture of Tails appears. Tails also appears in the Tornado, at the D.A. Garden/Play Music.
- The front cover of the Japanese version contains the message "To live a life of power, you must have faith that what you believe is right, even if others tell you you're wrong. The first thing you must do to live a life of power is to find courage. You must be ready to reach beyond the boundaries of Time itself. And to do that, all you need is the will to take that first step..."
- The prologue in the North American instruction manual is almost identical to its European counterpart. However, in the North American Sega CD version, Amy Rose is named Princess Sally. This was done to tie in with the Sonic the Hedgehog television series, in which Sally was the lead heroine. The manual describes the character as a young hedgehog, whereas in the television show Princess Sally is a chipmunk.
- This is the first Sonic game to include centiseconds in the time as opposed to just minutes and seconds.
- Loading the game CD into a regular CD player will enable one to hear the game's music.
- In the Japanese and European Mega-CD versions, the bad ending had the text "TRY AGAIN AND SAVE LITTLE PLANET FOREVER". In the North American release, the second line was removed, resulting in simply "TRY AGAIN". This change is retained in the PC port (which was based on that release) and the 2011 digital version, the latter of which may be due to the then-upcoming Sonic the Hedgehog 4: Episode II. The North American version had other minor changes besides the soundtrack, such as allowing the player to restart the level in their current time period at the cost of a life.
- This is the second Sonic game with voices, the first being SegaSonic the Hedgehog. When Sonic does one of two actions, such as when remaining idle for three minutes, Sonic will shout "I'm outer here!" and jump off the screen, resulting in a Game Over, or when getting an extra life, Sonic will shout "Yes!".
- Many players have believed that Sonic shouts "I'm outta here!" when he jumps off the screen and causes a Game Over. It was not until years later until Masato Nishimura, the landscape designer for the game and the one who provided the voice clip for Sonic, corrected this stating that Sonic actually says "I'm outer here!".
- Most of the sprites for Sonic come from Sonic the Hedgehog, with the exception of some, such as the Super Peel-Out, spring jumps, and the 3D images from the beginning of Palmtree Panic, Wacky Workbench, and Metallic Madness.
- Despite using sprites from Sonic the Hedgehog, Sonic does not bob up and down at all when he walks: his head stays perfectly steady.
- This is the first Sonic game in which Sonic runs with his arms held out backwards (either by using the Super Peel Out or moving at a fast enough speed).
- In Edit Mode, there are sprites of Sonic sneezing.
- In Edit Mode, an unused Monitor containing a silver ring can be added during gameplay. When the monitor is broken, the power up will give Sonic 50 rings and will make the lamppost sound effect.
- Ken Balough has stated that Sonic the Hedgehog CD has no official spot on the timeline other than it took place sometime before Sonic the Hedgehog 4: Episode I.
- According to Yasushi Yamaguchi in a 1993 article on the Japanese magazine BEEP Mega Drive, the story of Sonic the Hedgehog CD takes place between the original Sonic the Hedgehog and Sonic the Hedgehog 2.
- According to Masato Nishimura, the landscape designer for Sonic the Hedgehog CD, the timeline placement of the game is vague. He also refers to Yasushi Yamaguchi's old statement as a contradiction since Metal Sonic is more advanced than Mecha Sonic.
- This is the first Sonic game to utilize a game save feature.
- Sonic the Hedgehog CD (Sega CD) Japanese instruction booklet, pgs. 4-5.
- Sonic the Hedgehog CD (Sega CD) Japanese instruction booklet, pg. 6.
- Sonic the Hedgehog CD (Sega CD) Japanese instruction booklet, pg. 7.
- Horowitz, Ken (8 December 2008). Interview: Spencer Nilsen. Sega-16. Retrieved on 16 November 2021.
- "1999 Video Game Buyer's Guide". Electronic Gaming Monthly: 141. 1999.
- GameFan, volume 1, issue 12 (November 1993), page 22
- GameFan, volume 2, issue 2 (January 1994), page 18
- Electronic Games, issue 15 (December 1993), page 140
- Peeples, Jeremy (27 June 2004). Sonic CD. Sega-16. Retrieved on 19 April 2014.
- Chris; Mark (January 1994). "Sonic the Hedgehog CD". Sega Force Mega 2 (7): 102–4.
- Electronic Gaming Monthly's Buyer's Guide. 1994.
- Official Gallup UK Mega-CD sales chart, February 1994, published in Mega issue 17
- Mega magazine issue 26, page 74, Maverick Magazines, November 1994
- McKinley Noble (6 May 2009). The 20 Best Platformers: 1989 to 2009, Feature Story from. GamePro. Archived from the original on 2009-11-19. Retrieved on 2011-11-23.
- The 100 best games of all time, Xbox 360 Features. GamesRadar (2011-04-01). Retrieved on 2011-11-23.
- Masato Nishimura on Twitter (Japanese). Twitter (9 July 2017). Retrieved on 6 December 2018.
- Sonic CD – Developer Interview Collection; originally featured in BEEP and Marukatsu MD magazines. Archived from the original on 24 March 2020. Retrieved on 2 June 2020.
- Masato Nishimura on Twitter (Japanese). Twitter (13 February 2022). Retrieved on 21 December 2021.
- Sonic the Hedgehog CD at Wikipedia, the free encyclopedia.