From Sonic Retro
"What can be gathered from the concept art is that it had structures like the Aquatic Ruin Zone of Sonic 2. Also rainbow waterfalls. The background seems to be a cliff with grass on the top, meaning it probably didn't take place in the desert. Mountains can be seen further behind the cliff with grass on top.
What can be gathered from the uncut extended ending video is that there are metallic structures, perhaps pillars. Also stone tiling that collapses when Sonic gets near it. There are vines and other vegetation that grow in various places, again indicating the level probably didn't take place in the desert."
Ok, you removed this as speculation, but the only thing here that seems questionable is that the level takes place in a desert. But rainbows only exist around water. So unless it's a pretty big oasis I don't think the level could take place in a desert. Remember each zone is several acts long. Looking at the pics provided should make determining if the rest is true, easy. There are structures like Aquatic Ruin, Rainbow Waterfalls, There is something in the background with something that looks like grass on it, mountains behind it are easily identifiable. You can also see the metallic pillar to the left in the video, stone tiles on the floor, holes that form when Sonic gets near it, Vines can be seen on the ground, moss is seen in several places. Vines and moss don't usually form in a desert as far as I can tell.--MathUser 01:11, 6 March 2013 (UTC)