The Game Gear games do make it trickier, so I typically exclude them from my theory-crafting. Chaos Rush certainly had a nice breakdown though, influencing me to hypothesize some more. So here goes: 1. SegaSonic the Hedgehog - While it could probably be placed just about anywhere prior to Chaotix, it just feels right being first. The Sonic 1 JP manual states that Eggman has been foiled by Sonic before, which indicates some entry comes before it. Not really sure what plan they foiled here, but Eggman's base of operations was certainly disrupted. 2. Sonic the Hedgehog - Noted in the manual to not be Eggman's first encounter with Sonic. 3. Sonic the Hedgehog (GG) - Ideally this would fit within the Genesis version. I've come up with a possible sequence there if anyone is interested. 4. Sonic CD - Could be placed prior to Sonic 1, as I discount mechanics having bearing on the order. Lack of Tails is mainly why I place it before 2. It also has to be placed after Eggman had encountered Sonic at least once, due to Metal Sonic. 5. Tail's Adventures - The JP manual states that it is a prelude to Sonic 2. Could mean it could take place before/after/during the already listed. 6. Sonic 2 - The JP manual indicates that this is when Sonic meets Tails. 7. Sonic 2 (GG) - Eggman already had a hard enough time dealing with Sonic alone, so he kidnaps his buddy. 8. Sonic Chaos - Obviously has to follow Sonic 2. Lack of Knuckles is my main reasoning for having it here, but that doesn't necessarily have to factor in. 9. Sonic 3 & Knuckles - Sonic and Tails' story first, followed by Knuckles'. Had a thought that Triple Trouble could be sandwiched in there, since it appears to be on Angel Island. 10. Sonic Triple Trouble - This one is tricky, as it doesn't make much sense to me that Knuckles' would be tricked by Eggman immediately after taking down the Eggrobos... So it could take place after some or all of Sonic's story in 3K, or Knuckles is insanely gullible. 11. Sonic 3D Blast - Another tricky one, as it doesn't reference the events of past games aside from simply having Tails and Knuckles being nonsensical gateways to special zones. Their appearances are irrelevant to the plot, so this entry could take place anywhere. Maybe even before SegaSonic! 12. Chaotix - Has to follow S3K. Right? 13. Sonic Mania - Revisits past zones. Encore mode follows this if it is really canon. 14. Sonic 4 - Would prefer to not include this, but oh well. It claims to take place shortly after 3K, so it could possible be before Chaotix and Mania. 15. Sonic the Fighters - Could easily not be included, but I enjoy the theory that it can serve as a conclusion to Sonic 4. 16. Sonic Adventure - In my humble opinion this concludes the classic line, although it could also be viewed as a reboot. Release order seems good enough for the Modern line, simply omitting the storybooks and non-pivotal side-games like Shuffle or Chronicles. I'd probably place the first Advance after Adventure, then the sequels after Adventure 2. I also omitted Sonic Blast because I remember nothing about its story or if it even had one.