Sonic the Hedgehog CD (2011)

Sonic the Hedgehog CD
Developers: Christian Whitehead (iOS/Android/Windows Phone/tvOS), Blit Software (PS3/360/Windows/Ouya) Publisher: Sega Platforms: Android, Xbox 360, iOS, PlayStation 3, Windows, Windows Phone, tvOS, Ouya Released in JP: December 16, 2011 (Android), November 14, 2012 (Windows) Released in US: December 14, 2011 (Android/360), December 15, 2011 (iOS), December 20, 2011 (PS3), January 19, 2012 (Steam/Windows), March 31, 2016 (Apple TV) , August 1, 2013 (Ouya) Released in EU: December 14, 2011 (Android/360), December 15, 2011 (iOS), January 19, 2012 (Steam/Windows), August 2013 (Ouya) Released in KR: December 21, 2011 (PS3) This game has unused areas. This game has unused code. This game has unused graphics. This game has debugging material. This game has regional differences. This game has revisional differences. This game has a development article This game has a prototype article This game has a prerelease article This game has a bugs page

This page covers the 2011 multiplatform remake of the game, not the (different) 1995 Windows 95 port of the game, and not the 1996 Windows 95 port. You can find the 1996 version's page here.

The 2011 Sonic CD is the first-ever published Sonic the Hedgehog title running on Christian Whitehead's Retro Engine, faithfully porting pretty much everything the original Sonic CD had to offer in a widescreen 16:9 aspect ratio, plus some extras and improvements such as an unlockable Tails to play as.

This, along with the iOS remakes of Sonic 1, Sonic 2, and a brand new version of Sonic 3 & Knuckles, is part of the compilation Sonic Origins.

Sub-Pages

Development Info

Prototype Info

Prerelease Info

Bugs

Changes from the Sega CD Version What they didn't tell you.

Version Differences From mobile devices, consoles, PC, and mobile again.

Retro Engine Secrets

Developer Menu

As with future releases of the Retro Engine, there is a secret developer menu that allows the user to skip to stages and scenes throughout the entire game. Set byte 0xCCB (offset CAB in HxD) in the GameConfig.bin file to 1 to access this menu from the pause screen.

There is a mode in Sonic CD (RSDKv3) that allows the game to read object scripts as .txt files instead of the bytecode files. This is activated when the game can't find the file "Data/Scripts/Bytecode/GlobalCode.bin" (or "Data/Scripts/Bytecode/GS000.bin" on PC).

Unused Full Engine Rotation

All the animation files have an unused value, dubbed "Full Engine Rotation". It lets the object using the animation file rotate to any angle, instead of being fixed to multiples of 45 degres.

There is also a value that does the same as the default flag. The only difference is that it doesn't use rotated sprites, and instead lets sprites be freely rotated in-engine

An updated version of this effect would later be used in Sonic Mania, though more sparingly, as it does not trigger when going up or down slopes of less than 45 degrees.

Unused Graphics

Menu Sprites

Artwork	Name	Description
	Swipe & Tap and D-Pad	This appears to have been a cut feature from the Mobile versions, most likely being a manual toggle between the use of touch controls or a gimmicky new scheme where you would swipe to run and tap to jump.
	Final Fever	While "Final Fever" is the title of the Japanese final boss theme, Christian Whitehead stated that during development this Final Fever was to be the name of a new boss stage. However, the level was cut due to Sega wishing to remain faithful to the original game. This text can be seen in-game if the stageID is incremented past Metallic Madness Act 3 Bad Future on a save file.
	"Sega CD BIOS" Sonic	A sprite of Sonic, most notably used during the Sega CD BIOS boot. As it is present next to Sonic's sprite for the character select screen, it is safe to assume this once occupied that slot before the newer sprite took its place.
	Unused RAM Data Icons	Unused Sonic and Tails icons that were found in MenuGfx2_EN.gif. The Sonic icon was originally used in the RAM Data screen. Instead, in the remaster, when a slot is removed, chibi versions of the character with "No" sprites are used. The presence of a Tails version could possibly indicate that the Save Slot screen would've much more closely resembled the RAM Data screen.

Miscellaneous Sprites

Name	Artwork	Description
SEGA Logos	Unused / Origins Alt Unused Version (PC / Consoles) TM Ver. / RAW Restored	Unused SEGA logos from the startup screen. The first SEGA logo was later used in the Origins version. This is a leftover from the concept demo. The second logo can be found in the PC/Console releases.
Trademark Sprite		Intended for the logo on the title screen.
Unused Controls		A leftover from the concept demo.
Sonic Idle		An animation of Sonic tapping his foot, intended for the Special Stage. This was taken from the 1996 PC version, which itself is taken from unused sprites in the Sega CD version.
Upside-down Tails		Unused sprites of Tails upside-down, much in the same vein as unused sprites in the Sega CD version. The third frame has no transparency whatsoever.
Tails Idle		An animation of Tails tapping his foot, intended for the Special Stage. This is also based off of unused sprites in the Sega CD version.
Unused Projector		An animation of a sheep being stomped is found within the files for Metallic Madness. It's likely this would have been used for a Metal Sonic projector in Metallic Madness, which has none in both the original game and this remake.
Demo Text		Text saying "Demo". It's likely that this text was intended to show during the in-game demos.
Script Icon		The default icon for level objects in the Retro Engine's Scene Editor. Obviously, this doesn't go used anywhere in-game.
Time Attack Placeholder		A "?" placeholder graphic.
Time Attack Exit	Unused Used	The image that occupied the Exit selection of the Time Attack screen in the Sega CD, 1996 PC, and GameCube versions, but with the "Exit" text adjusted slightly to more closely resemble the title screen. This can be seen in the Xbox 360 version by pressing B to exit Time Attack, then pressing A to select any Special Zone just before the transition to the main menu. This takes the player to the hidden eighth Special Stage, with the giant Eggman head in the background. This sprite is used in the mobile version of the game in the "About" section, though with the background removed.

Animations

Sonic and Tails' animation files (as well as their Mini versions) have unused animations that are mostly empty, except for Sonic's Corkscrew H, which actually has 12 frames that use values from one of Whitehead's Sonic fan games, Retro Sonic. Because the animation values were made for Retro Sonic's sprite sheets and weren't updated for the CD sprite sheets, they appear as just random parts of Sonic's sprite sheet. The animations relating to ledges, climbing, and sliding could be leftovers of Knuckles' inclusion, either from the Retro Engine or a scrapped plan to include him.

   Sliding
   Gliding Drop
   Gliding Stop
   Climbing
   Ledge Pull Up
   Corkscrew H
   Corkscrew V
   Finish Pose

Manual Sprites

The final game uses PNGs in .arc files, but .gif sprite sheet versions of the pictures the manual uses exist for some reason. These are used in the mobile versions, as they don't use .arc files.

Unused	Used

Pictures

Located in the .arc files.

Artwork	Name	Description
	Onan Games Logo	Logos intended for the studio Onan Games. Confusingly, this port doesn't appear to have any official connection with this company, outside of this image in the .arc files. The console versions have an alternate version of this image with a white background.
	Wallpaper	A simple wallpaper that was used as a loading screen on older versions, but was later removed and has been unused since then. However, if you use the "Download Latest Compatible Version of the App" feature on iOS 6-7, you will get an older version of the game that has this wallpaper when you open the game. For Android, you'll need to find an older APK (Android package file) of the game. Also, this image is stored in all versions of the game.