Sonic CD (Sega CD)
|Sonic the Hedgehog CD|
This game has unused areas.
This game has a prototype article
Sonic CD is just your average Sonic the Hedgehog game on a CD... that's what you're told, anyway.
Press Up, Down, Down, Left, Right, B at the title screen. Note that you will be taken back to the title screen upon completion of the selected level.
Sound Test/Debug Mode
At the title screen, press Down, Down, Down, Left, Right, A to go to the sound test. By entering the following codes, you can get the corresponding image, debug mode, and/or extra after pressing Start.
|Tails next to a fourth-generation Lotus Seven, with the words "SEE YOU NEXT GAME" above it. This code also activates the debug mode: like the previous Sonic games, press B to change from Sonic to an object, A to cycle through objects, and C to place an object on the screen. It's worth noting that Judy Totoya, creator of Tails and designer of this game's Special Stages, is mentioned here. Also, the Tails unlock screen on the 2011 remake says "SEE YOU NEXT GAME", most likely as an Easter egg.
The "Little Planet" theme plays here.
|An unusual Batman tribute. The final boss music plays in the background.|
|Sonic, Metal Sonic, and Eggman gettin' funky. This "official" art plays the Metallic Madness Present music.|
|A cute Sonic with grey eyes. The Palmtree Panic Good Future music plays here. The message says "ゆーあーくーる" (You are cool, by Sanchanzu).|
|A rather creepy wallpaper collage featuring multiple Sonics with a freakish humanoid face. The boss music plays. The Japanese text roughly translates into "Fun is infinite with Sega Enterprises. - Majin".
"Majin" is a childhood nickname of artist Masato Nishimura, as explained here.
|The text "WELCOME TO SECRET SPECIAL STAGE" will appear, after which that stage will load (see below).|
Unused Special Stage
As mentioned above, setting all three Sound Test selections to 07 will load this stage that features the enlarged head of Eggman as its background and has a rather difficult layout. It's possible that an extra Time Stone was to be collected here at one point, though it's probably just a little bonus thrown in for curious players, much like the hidden pictures.
|Sonic with eyes closed||Sonic with his eyes closed. Could have been used as part of an idling animation, akin to Sonic 2's two stages of waiting, and Sonic 3's unused animation of Sonic nodding off to sleep.|
|Sonic being electrified||An animation of Sonic being shocked by electricity. It may have been used in Wacky Workbench, which contains various level elements with the potential to electrify the player. It could also have been used in Collision Chaos as part of the Metal Sonic sequence.|
|Sonic falling||An animation of Sonic falling into the distance. Purpose unknown. A similar animation is present in Sonic 1, also unused.|
|Sonic waving his arms||An animation of Sonic waving his arms with his palms outstretched. This could have been used in Tidal Tempest when walking through the water, to simulate an attempt at moving more quickly.|
|Sonic looking backwards||Sonic looking over his shoulder. Purpose unknown.|
|Sonic sneezing||An animation of Sonic sneezing. Purpose unknown.|
|Sonic upside-down||An animation of Sonic upside-down with his eyes wide and his mouth open. This suggests that this animation could have either been used for an alternate death animation, or if Sonic was caught by an environmental hazard that dangles him in the air somehow.|
|Sonic grabbing||Sonic grabbing onto something and attempting to create traction. This implies that he may have been trying to stop something from pulling him into some sort of hazard. Part of a scrapped badnik, maybe? A modified version of this sprite appears in Sonic Crackers.|
|Sonic on horizontal pole||Similar to the other horizontal pole sprites from Wacky Workbench, this one has Sonic swinging his feet forward. Perhaps he originally had to pull away from electrical hazards positioned underneath?|
|Sonic shrugging||An animation of Sonic shrugging his shoulders. Note that his spikes rise during each frame – some believe this implies a transformation into Super Sonic, though that is purely speculation. These sprites are found in SPSS__.BIN, which contains Sonic's Special Stage-specific sprites.
In the final frames of the animation, the very bottoms of his feet disappear, as though he is sinking into something. Perhaps an unused quicksand hazard, or even being pulled out of the Special Stage altogether, as a "failure to obtain the Time Stone" animation judging by his annoyed frown in the last few frames.
|Sonic hanging||An animation of Sonic being pulled up by...something. Purpose unknown. These sprites are also found in SPSS__.BIN. Early screenshots show hot-air balloons, not UFOs, in the Special Stages; perhaps they caught Sonic and floated him around?|
|Sonic falling back||An animation of Sonic being knocked back. Purpose unknown. These sprites are also found in SPSS__.BIN.|
|Sonic leaping||Purpose unknown. These sprites are also found in SPSS__.BIN.|
|Sonic with chest forward||An animation of Sonic with his arms outstretched and his chest pushed out in front of him. While its purpose is unknown, some believe that this is somehow related to transforming into Super Sonic.|
|Sonic skidding||An animation of Sonic skidding whilst looking the other way. It is unused in the main game, but does appear during the "You Are Greatest Player!" sequence seen once beating the Time Attack scores. It's fairly similar to the skidding animation in Sonic Crackers, and could have been used while skidding at higher speeds in contrast to the normal skidding animation, which was modified from Sonic 1.|
|Unused Amy sprites||Sprites of Amy with hearts in her eyes. While they go unused here, they are used in the 2011 remake.|
|Oil Slick||Oil slick used in Special Stages that cause you to slip. These can be found normally in some prototypes of Sonic CD, but are unused in the final.|
|Broken Switch||It has been speculated that they may have been used in the Bad Future of a Zone, to prevent access to certain routes. Other switch sprites present for comparison.|
|Platform||Moves up and down while moving to the left. It comes in two variations: a pair and a group of four, all of which do the same thing (though in the latter, the top row are flipped vertically). The object belongs to the Present version of Quartz Quadrant Zone.|
|Hand||Appears to be an unused Special Stage item. Purpose unknown, but may have stopped the timer.|
Almost the entire soundtrack was redone for the American version by Spencer Nilsen because Sega of America thought the soundtrack of the Japanese and European versions sounded too identical to the electronic dance soundtracks being produced at the time, so the American soundtrack has more of a rock feel. One example of this is the theme song: instead of "You Can Do Anything", the American version has "Sonic Boom". The only songs that weren't altered were the Past themes, since those were played through the PCM chip and not Redbook.
In addition, there are a few other differences in the American version compared to the original Japanese and European games:
- Some of the music placement was switched around. For example, the "Little Planet" theme now plays on the Time Attack screen (rendering the title theme copy unused), and the music played during the Metal Sonic race is now the normal mix of Stardust Speedway's current Future and not always the "B" Mix.
- The player can restart the stage at any time by pressing a button while it is paused, eliminating some potential time warp issues. This is at the cost of one life.
- There are no longer sound effects at the beginning of the ending. Due to the extended "Special Edition for North America" credits, the ending theme plays over the entire video and mutes other audio (including the post-credits).
- The bad ending's "TRY AGAIN AND SAVE LITTLE PLANET FOREVER" text was shortened to simply "TRY AGAIN".
- The special "YOU ARE SUPER PLAYER" screen now includes "A" to remove Engrish.
- The copyright text at the title screen was altered slightly.
All of these changes are also in the PC version, though the 2011 re-release reverts the Metal Sonic racing theme so it always plays Stardust Speedway "B" Mix and mostly restores the original ending videos' exclusive audio when played with the Japanese soundtrack.