During the development, when the project changed its name from Round2.exe to Sonic: The Second Round, Super Sonic wasn't planned yet. It was a secret in previous releases but eventually the monitors in Last Chance were replaced with the Chaos Emeralds to add more background to the Fake Sonic (at least in this game). This incarnation is neither an entity nor a demon, but rather an organic clone created by the use of the negative energies of the Chaos Emeralds and Sonic's DNA. Unlike others like Zalgo, X, Exetior or any others, this one doesn't have a name. Since the positive energies were still intact, Sonic is still able to become Super (Inspired by Sonic Adventure).

With Super Sonic confirmed, we decided to include the game's name in his pre-battle cutscene, since he fights against his doppelganger for a second time.

Since the pink-eyed* clone was created with the negative energies, I decided to give him a second form as well. No exaggerated stuff with lots of teeth, monstruous faces or tentacle-like quills. Simplicity is better sometimes.

Another fun fact: The death scene of Sonic's doppelganger already existed in much older versions of the project, where he is petrified and explodes shortly afterwards. I didn't want to make another bloody mess, so I reused this concept.

*pink-eyed - reference to an eye inflammation called "Conjunctivitis", also known as pink-eye.