I found out there is a funny glitch where the game thinks you are playing as Knuckles in stand alone Sonic 3! I was glad to find that out. Back in the day I would use debug to go on Knuckles routes as Sonic and then with Sonic 3 and Knuckles vice versa. I thought that would be a great way to play through the game!!
First I would go on Knuckles route even though parts of the game are impassable. Then I would finish the level Sonic's route too as 'Knuckles' in Sonic form today! Hehe we will save that for part 2!
This is Level 1 part 1 - Going Knuckles route in Angel Island. I'm glad to play through this game again!