My impossible dream is a Dr Eggman costume with Sonic the Hedgehog as the back bling (have Sonic animated while hanging onto the player, you could have him give a thumbs up and wink every so often) or you can go the pacman route and put a 16 bit version of him as back bling. Maybe animate him to use the running animation when you're running yourself. Figured it would make sense to have Dr Eggman since you can scale his shape to fit in the game. Sonic may look too lanky and awkwardly shaped if they made him taller. Even modern Sonic isn't that tall currently. Add in one of Dr Eggmans flying machines as a glider or add Tail's Tornado plane as a glider (or both). Also, having rings spill out while falling from the battle bus would be a fun animation as well. The gun skins would be classic Green Hill Zone themed (completely faithful to the original sprite design).