What Sonic development secrets do we have left on the list?

I'd for one love to see the old rotating special stage build. I've always loved the Sonic 1 Special Stage, and the rotating one in the first screenshot seems much more interesting and fun than the one we got (not that I have anything against the CD special stage).

 

What was Phoenix Rie's favorite lunch during the development of Sonic 1?

Important stuff, fam.