Some time after the events of the first Sonic the Hedgehog video game, Sonic the Hedgehog visited Never Lake where the "Little Planet" appears once a year. The hedgehog is accompanied by new friend Amy Rose, but she is soon captured by a new Metal Sonic who takes her to the oddly-metallic Little Planet. It's down to Sonic to thwart Doctor Robotnik's new plan, fight off Metal Sonic, find the seven Time Stones and rescue Amy. A tall order for anyone other than Sonic the Hedgehog!
Sonic CD contains seven Zones, each of which contains three acts. Unique to this game is the fact that each area has four different Time Zones (Past, Present, Good Future and Bad Future) which can be travelled between by running quickly past signposts for a few seconds.
- Palmtree Panic Zone
- Collision Chaos Zone
- Tidal Tempest Zone
- Quartz Quadrant Zone
- Wacy Workbench Zone
- Stardust Speedway Zone
- Metallic Madness Zone
As well as these, Sonic can enter a Special Stage that involves him destroying six UFOs for Time Stones. Getting all these wins players the Good Ending that sees the Little Planet free from its metallic confines and leaving the dimension. Fail to do this and Robotnik will win, fleeing with the remaining Time Stones as the Little Planet remains a metal monstrosity.
BadniksThe original European release featured no names for the Badniks found in the game, so many went unnamed when they appeared in Sonic the Comic. The PC release reunited them with their Japanese names. Only a few appeared in STC and some that were meant to be from the game were actually original designs:
The Encyclopedia Badnika, a section in Sonic the Comic Online, goes further to say the Badniks were powered by flowers on the planet as a temporary power source until the power was metallised. The "author", Norris Wimple, stated that they had never been named, but Megadroid confirmed they had Japanese names.
Sonic CD was the first Sonic game to get a full adaptation in Sonic the Comic and was the longest-running adapted story arc, beginning with Girl Trouble in Issue 22 and not fully ending until Issue 79's Return to the Miracle Planet (although a loose story thread was tied up much later in Issue 255's Many Happy Returns). The plot was largely the same, with the Little Planet (known here as the Miracle Planet) getting chained to Never Mountain. The Metal Sonic, known as Metallix, kidnapped Amy which led Sonic heading to the metallic planet to free her. In his attempt to beat his new foe, Sonic ran around the entire planet and went back in time thanks to his tiny future self. Sonic grabbed a Time Stone and made sure that the technology couldn't multiply across the planet, also destroying the Metallix.No other Zone other than the Palmtree Panic Zone featured in the comic at all, although the rusty landscape coupled with a shrinking ray is very similar to the Metallic Madness Zone. The Freedom Fighters also visit a cave which could be part of the Quartz Quadrant or Tidal Tempest Zones. Aside from this, the Palmtree Panic Zone became a holiday getaway for the heroes and later became the place to evacuate Mobian children when theDrakon Empire began their war on the planet.
The two new characters introduced for the game, Amy and Metal Sonic, became extremely popular additions to the STC continuity. Amy became a leading member of the Freedom Fighters who got her own series, as well as one with original character Tekno the Canary. Metal Sonic was soon linked to the Brotherhood of Metallix, an army of Metal Sonics that managed to rewrite history and eradicate almost all life on Mobius. Once they were destroyed, individual Metallixes appeared sparingly and a new series of Metallix Mark 3 Badniks were based on Knuckles the Echidna.
- One News Zone segment revealed that the game was to be called CD Sonic and that Amy was Sonic's new "girlfriend", something that was a major point in several STC stories.
- Tony Takoushi produced a preview of Sonic CD in Issue 9's News Zone, compiling information from older news stories as well as teasing more new information.
- Part of the state-of-the-art opening cutscene was reproduced in The Sonic Terminator, with Sonic rushing across the landscape and spinning through boulders thrown by Metallix.
The game was heavily built up in early editions of Sonic the Comic, with information on the game appearing in at least three news segments. When it eventually made it to the Review Zone in Issue 15, Vincent Low awarded the game 90%. Low complimented the "brill graphics, sound and playability" but believed there wasn't "alot [sic] that's new", despite the completely new feature of time travel as well as 3D special stages and new techniques.
There have been many discussions in the Message Zone about the game, with many claiming that the title is their favourite Sonic game. There are those that consider the game to be inferior to all other 'classic' Sonic entries, but many concede that the added depth of time travel makes Sonic CD a rewarding experience.