Holy $#!7! This is like my favorite game EVAH!!
I even remember the little trick to get to the debug screen.
Use notepad or something to edit the "sonic.ini" file in the "windows" directory. Add the following line to the file:
[Secret]
User=Debugger
(Yes, capitals are important here) Start up the game and two new menus will appear. The "Stage" menu will allow any stage (including Special Stage 8) to be selected. The "FUNC" menu has the ability to turn on debug mode, turn off the special stage timer, record and play a demo, and uncheck the MMTimer option to place the game in turbo mode.