I had a look on Icecap zone yesterday, and found out a place were there's a very cool vertical scrolling BG, it's inside the caves.
Sega was awesome for adding so many GFX touches in S3&K!
Compared to S1&2, it was like running on another console.
I was really depressed when 32X was limited with the poor Knuckles Chaotix.
And I wonder what was supposed to be a Sonic 4 at that time. (wasn't confirmed any development on it, but appeared in the 32x upcoming titles after all)
By the way, the 32X had a different sound chip? Or was it the same as Megadrive?