Sonic CD

, or simply Sonic CD, is a platform game in the Sonic the Hedgehog series. It marked the first official appearance of the characters Metal Sonic and Amy Rose. It was released for the Mega-CD in Japan on September 23, 1993, in Europe in October 1993, and finally for the SEGA CD in North America on November 19, 1993. The game was ported to PC CD-ROM in 1996 as part of the Sonic Gems Collection. It is also available on Steam for Microsoft Windows.

Storyline
Sonic comes to Never Lake, after destroying Scrap Brain in Sonic the Hedgehog. He comes to the fabled Miracle Planet, and meets a female pink Hedgehog named Amy Rose. She follows him around until a Robot, named Metal Sonic, kidnaps Amy; Sonic gives chase. His pursuit leads to confrontations with Dr. Robotnik and Metal Sonic, culminating with a race against the latter, to save Amy, and a showdown with the former.

Good Ending: Sonic collects all the Time Stones, destroys the planet and leaves Amy in Never Lake as he watches the planet being destroyed and then sets off for another adventure.

Bad Ending: Sonic doesn't collect all the Time Stones, he leaves Amy in Never Lake as he watches the planet floating away and Robotnik has taken the Time Stones away.

Whichever ending occurs, the game's story take place between Sonic the Hedgehog and Sonic the Hedgehog 2.

Gameplay
Sonic's gameplay remains similar to that of Sonic the Hedgehog but with the addition of the Spin Dash and the Super Peel Out, which lets him zoom into a quick speed from a standing point.

The game is set across seven different zones, all of which have alliterative names. These are:

The main innovation of this chapter in the Sonic series is the manner in which the player can travel to four different versions of each zone, each a different time period of the same location: Present, Past, Good Future and Bad Future. This is accomplished by speed posts scattered around the level, bearing the labels "Past", and "Future". After running through one of these posts, the player has to run at top speed for a few seconds without stopping, to travel into the respective time period. Because these teleports are relative, there are no "Past" signs in the Past, and no "Future" signs in the Future; that is, warping to the past in the future returns the player to the "present" time and vice versa. Each stage has three "Acts" (Although they are called "zones" in this game, see below), the third of which always takes place in the future.

The different time zones have slightly different layouts and sprite placements, as well as significant changes in the level music, art and palette. In addition, the robots within a level fall into a state of disrepair as time passes; in the present, some machines have become worn down while in the future all of them have. This affects the speed and attacking ability of the robots; some of them become completely ineffective, while others do not significantly change.

The appearance of the future changes depending on the actions of the player in the past. Hidden within the past of every level, there is a robot generating machine. If this is destroyed within a zone or all seven time stones are already collected, all of Dr. Robotnik's robots will be destroyed in the past. Should the player warp into the future, it is a "Good Future" in which there are no enemies and fewer hazards. If the machine is not destroyed, the warp will lead the player into the "Bad Future" in which Dr. Robotnik's robots run rampant, there are more hazards (though due to wear on some of the enemies, not always as many as in the past), and heavy pollution and crippled construction has harmed the level.

In addition to the robot generating machine, hidden within the past of each level is a machine which projects a hologram of Metal Sonic squashing one of that particular zone's animals underfoot. Destroying this machine causes animals to appear in the past and present levels. However the animals are always present in the Good Future, regardless of whether or not this machine was destroyed.

The third zone always takes place in the future and is mainly a short run up to the boss. Most boss battles are more elaborate than those in the other Sonic games, and typically require fewer hits than the usual 6 or 8. These boss battles, however, require more effort to actually hit Robotnik; one battle takes place on a makeshift pinball table and requires the player to use flippers to get up to Robotnik. Two battles do not involve hitting Robotnik to damage him; one takes place on a giant treadmill where the objective is to wear out Robotnik's machine by running on it, and the other is a race against Metal Sonic. The appearance of the third zone depends on the player's actions in the other two; if the player has achieved a Good Future in the other two zones (or all the time stones are collected), this zone will be a Good Future as well. However, if only one or neither stage has been made into a Good Future, the third zone will be a Bad Future. If all the third zones have Good Futures, the player is able to see the good ending but if the player gets all gems and all good futures, then a bonus ending is seen.

As in 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 50 rings, whereas in the Sonic the Hedgehog 2 checkpoints are used to enter special stages. It is because of this that there are speculations that Sonic CD began development before Sonic 2. A giant ring will float above the finishing sign which Sonic can jump through to enter the special stage. They consist of a three-dimensional, flat surface. To complete a stage and collect the Time Stone reward, the player must seek and destroy six purple UFOs flying around the stage, whilst avoiding spike traps and water (which causes time to decrease faster). If a UFO is destroyed, it gives a prize of either a super ring (have gold markings and give progressively larger bonuses starting with 20 rings when destroyed in series) or speed sneakers (have grey markings and temporarily boost speed). When the player is running out of time, an additional lighter-colored UFO with red markings will appear; destroying it will give the player more time. Collecting the seven time stones, only possible in the special stage, automatically guarantees that the player will reach the good ending even if one of the previously completed zones did not have a Good Future, and that all futures of upcoming zones will be good as well.

Sonic CD was the first Sonic game to use a backup save, using the internal SEGA CD memory or a backup RAM cartridge. The game saves after the end of each third act (after which, a new level begins) and records the best times of the player in the time attack mode. Interestingly, this game also features an instant game over scenario. If the player leaves the game unpaused and doesn't move Sonic for three minutes, he'll say "I'm outta here!" and jump off the screen, instantly ending the game regardless of lives.

Characters

 * '''Sonic the Hedgehog
 * Amy Rose
 * Metal Sonic
 * Dr. Ivo Robotnik
 * Tails (appears only in a picture with a code)*

Development
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 (already known as Sonic Team) 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 (or at this point, "CD Sonic" as it was first known ) was handled by a separate development team, headed by Sonic creator Naoto Ōshima. Initially, as revealed in interviews and magazine clippings, Sonic CD, and Sonic the Hedgehog 2 for the Mega Drive/Genesis, Master System and Game Gear were supposed to be the same game. However, during development, Sonic 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 CD are different, as well as the use of most of the original Sonic the Hedgehog's sprites for the latter title. The time posts also had sprites similar to Knuckles' Chaotix. However, some vestiges of the original tie-in remain.

Sonic CD was released after Sonic the Hedgehog 2 but before Sonic the Hedgehog 3/Sonic 3.

Music
The Japanese and North American versions feature two different soundtracks, with the European and Australian releases sharing the Japanese soundtrack. The Japanese soundtrack was composed by Naofumi Hataya & Masafumi Ogata, and featured songs by Keiko Utoku. The songs were entitled "Sonic - You Can Do Anything" (known also as "Toot Toot Sonic Warrior", composed by Masafumi Ogata) and "Cosmic Eternity - Believe in Yourself" (composed by Naofumi Hataya).

The boss music for the Japanese version was also noted for sampling the song "Work That Sucker To Death" by '70s American artists Xavier, Bootsy Collins, and George Clinton.

The North American version was delayed a few months to have a new soundtrack composed by Spencer Nilsen, who did other SEGA CD soundtracks as well as some early Sega Saturn soundtracks. All the music (save for the "Past" tunes, which were in PCM audio rather than Red Book CD Audio) was replaced, and new themes were composed. The new theme was "Sonic Boom", performed by Pastiche (Sandy Cressman, Jenny Meltzer and Becky West). Both the opening and ending had similar lyrics but different instrumentation. This is credited as the "Special Edition for North America" soundtrack. The lyrics for the opening theme were found in the back of the game manual.

The intro and ending FMV sequences were slightly re-edited to fit in time with the respective music. Since then, every re-release of the game in North America and Europe (where its original release featured the Japanese score) exclusively boasts the North American soundtrack, including both the PC version and the one in Sonic Gems Collection (the latter having the Japanese soundtrack in Japan but with the slightly altered programming of the North American version's) as well as in the special features section of Sonic Mega Collection; the Japanese soundtrack has never made it to North America. However, it has surfaced in Sonic Screensaver and Sonic Jam and has several remixes in some 8-bit Sonic games.

This resulted in controversy - GameFan, which had given the Japanese/European version a perfect 100% score, offered the North American release ratings in the 70% range, and made clear that this was due to the soundtrack change alone. GameFan's editor, Dave Halverson, later called it "an atrocity which remains the biggest injustice in localization history: worse than taking the farting mama out of DJ Boy, or the fruity mid-boss out of Streets of Rage 3. The company line was that American consumers weren't ready for techno... Prodigy burst onto the rave scene in the early 1990s and achieved immense popularity worldwide, but the US needed elevator music for the first arranged Sonic."

Nilsen would later state his view on the controversy: "They had all been playing the Japanese version for weeks or months before our version hit the streets, so it was like we replaced the music to Star Wars after the movie had been out for a while. From that perspective, I can't blame them."

If the Sega CD version of Sonic CD is played on a standard CD player, one can listen to all the "Present" and "Future" stage music with each "track" having a different song. The "Past" stage music is PCM audio and can only be played through the game's sound test. However, the PC port includes the past soundtracks in the Red Book standard as well nearer to the end of the CD.

One of the last North American development versions of Sonic CD contained the Japanese soundtrack completely intact. Ultimately, the soundtrack was completely replaced.

Notably, a remastered version of "Sonic Boom" was used as an unlockable music piece for use on a Sonic the Hedgehog-themed stage in Super Smash Bros. Brawl. This revision of the song is based on the opening movie version, but features slightly improved instrumentation as well as having been reconfigured to loop. This song is present even in the Japanese and PAL versions of the game.

Most of the music from Sonic CD was released on a special edition album called Sonic The Hedgehog Boom. The album is now out of print and somewhat rare.

Palmtree Panic present (EU/JP) is an unlockable song in Mario & Sonic at the Olympic Winter Games and Sonic & SEGA All-Stars Racing.

Reception
Reviews for Sonic CD were generally positive, with a consensus that it was the best game for the Sega Mega-CD. The game was praised for its innovative time-travel based gameplay, presentation and music. Despite this critical acclaim, however, the game failed to emulate the commercial success of other Sonic installments, due to the unpopularity of the Sega CD. Yet according to vgchartz.com it sold 1.5 million copies worldwide, 1.02 million in the US alone, and 480,000 in the rest of the world including Japan. It was the only game on the SEGA CD to sell anywhere close to a million copies.

Reviews for the PC version were subpar. Many reviewers didn't like how it played on PCs at the time compared to the smooth gameplay of the SEGA CD version. The PC version also didn't work on computers running later Windows OS systems Windows XP, Windows Vista, and Windows 7 due to some missing files (However, it worked on Windows ME and Windows 2000). However, a program called "Sonic CD PC Fix" solved those problems.

Sonic CD was awarded Best Sega CD Game of 1993 by Electronic Gaming Monthly. It was also listed at the #1 on the best Sonic game article on ScrewAttack's "Best and Worst Sonic games".

Ports
Sonic CD was ported to PC CD-ROM in 1996, marking Sonic's debut on the PC under the SEGA PC brand. This version was released in Japan on August 9, 1996, in the United States and Canada on August 26, 1996, and in Europe on October 3, 1996. A noteworthy change, the complete FMV animated intro and ending sequence was made available. The Japanese version of the game had its manual translated from the US version, and all versions had the US soundtrack, with the "Past" tunes converted to normal CD tracks.

While the DirectX version of Sonic CD for PC is the most common and the best-selling initial commercial game for Windows 95, it is not the first version of Sonic CD for PC. The original version of Sonic CD for PC was powered using Dino libraries, an Intel-developed precursor to DirectX. This version of Sonic CD was never individually sold at retail, it was only sold with Packard Bell computers as a pre-installed game, and sold as double-packs along with other PC Sonic games. Upon the release of DirectX 3.0, SEGA ported the Dino dependencies to DirectX calls and released Sonic CD in its DirectX form.

The PC port of Sonic CD is only playable on the older operating systems like Windows 95, Windows 98 and Windows ME. The DirectX version of game can still be played on Windows XP or Windows Vista via a fan-created patch called SonicCDFix. However this patch doesn't support the Dino-library-based edition of Sonic CD.

In addition to the PC port, Sonic CD is part of the GameCube (and, in Japan and Europe, PlayStation 2) compilation Sonic Gems Collection. This version is ported from the PC version with some enhancements regarding the game's frame rate and action speed (with no frame rate slow-down), however it also suffered from minor graphical errors such as scrambled backgrounds and the lack of color in the water from Tidal Tempest. The soundtrack in this version depends on the region, though European versions of the game contain the American soundtrack (unlike previous European releases which featured the Japanese soundtrack). This version also included the highest quality versions of the animated intro and ending sequences.

In July 2009, a developer named Christian Whitehead created a proof-of-concept version of Sonic CD running on the iPod Touch. Developed using his Retro Engine, it is based on the original SEGA CD version. Shortly after being shown the proof-of-concept, SEGA asked the fans on their website which game should be made for the iPhone or iPod Touch, hinting an official version might be made.

The game's story was also adapted in the British publication, Sonic the Comic.