Seeing as I’d left Sonic “parked” on Wing Fortress, I wasn’t surprised to finish this almost immediately after starting to play it today. Super Sonic made short work of the boss at the end of Wing Fortress, and Metal Sonic and Eggman proved to be no challenge at all.
However, although I got the achievement for completing the game, I need to go back and do it again, only more quickly! There’s an achievement for doing Chemical Plant 1 in under 45 seconds, and another for doing the game in under an hour. It should be easily gettable, it’s just I spent so long hunting rings on this run through that I spent way too long on it.