I will put in the list of games in order of my idea of canon, with brief explanations where needed. Spoilers of Generations ahead, so don't view if you don't want them.
- Sonic the Hedgehog
- Sonic 2
- Sonic 3 & Knuckles
- Sonic Generations (from Classic Sonic's viewpoint)
- Explanation: Classic Sonic starts off traversing Green Hill Zone for fun after beating Robotinik, and then the rest of the game unfurls. After seeing Modern Sonic boosting, using the Homing Attack, and other abilities, he goes of on a chain of adventures in attempt to learn these skills.
- Sonic Chaos
- Sonic Triple Trouble
- Sonic 3D Blast at the same time as Tails Adventure
- Explanation: Sonic decides that he needs to go on solo adventures in order to perfect the new moves, and thus, splits up with Tails until the events of SA1.
- Sonic CD
- Sonic the Hedgehog 4: Episode 1 (the point where we go into Dreamcast and Modern eras)
Hope you like it. Feel free to comment on changes that need to be made- I probably screwed up a bit since I became a fan of the series in the very late Dreamcast era. (Sonic Heroes, to be exact)