From Sonic Retro
For the remake of Sonic CD released in 2011, engine creator and asset porter Christian "The Taxman" Whitehead had developed a new Zone called Desert Dazzle, including artwork and level layout, before cancelling it and removing it from the final game.
A mock-up image of Desert Dazzle can be found by entering a special code on the music player/sound test screen: Simply enter PCM:32 and DA:8. This code will also enable the player to choose Tails when choosing a Zone from the Stage Select menu.
The level was an original creation based on the creator's own idea. The Taxman had created an early demo track for the level, but multiple regional soundtracks hadn't been taken into account yet. The demo track ignored the multiple regional soundtracks, so new music would have to have been created for each region.