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).
It's also accessible in the pause menu on some of the prototypes, as they're debug-enabled.
Watch on YouTubeAll 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.
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.
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 and from the June 22nd, 2011 prototype. The second logo can be found in the PC/Console releases.
Trademark Sprite
Intended for the logo on the title screen.
Unused Controls
Used in the June 22nd, 2011 prototype. The Tails Jump button is unused.
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.
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
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.
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 the older iOS 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. Also, this image is stored in all versions of the game.
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Development Info
Prototype Info
Prerelease Info
Bugs
Changes from the Sega CD VersionSay whaaat?.
Version DifferencesProbably more or less stuff here than the Sega CD Version.
