Ahh Headcanons, fun topic. Let's go: - Sonic 1 is a follow up to Sonic Manga, where Robotnik crashes the Sonic's Band concert. Then Sonic band just disbands, and he decides to dedicate his life to fight Eggman. - Knuckles story from Sonic 3 & Knuckles , runs concurrently to Sonic campaign. That's why Angel Island is unscathed in the first zone, and that's why Knux fights Eggrobo - because Eggman doesn't want to reveal his true intentions. Then, in the end he fights Mecha Sonic, while Sonic and Tails deal with the DeathEgg. - Gemerl actually has access to Emerl memories/databanks, but he's basically a different robot. Sonic doesn't interact with him much, because the memories of a friend, who he couldn't save are painfull. - The SMS games are canon, but it's *another time, another place* case. - Archie Comics, Fleetway, Boom, Sonic X are just another universes, but all happened and are canonical to itself. Sonic Chronicles too. - The "modern" chaotix remember Knuckles, Knuckles remembers them from Chaotix. They just don't reminiscent of the good old days. - Tikal still lives in the Master Emerald, but she doesn't show up, because Chaos is now at ease.