Sonic the Hedgehog 4 is still a few years away, but theories about the story of the franchise's next installment have flourished ever since the post-credits scene of Sonic 3 hinted at what is to come.

New Sonic 3 concept art has emerged and has swiftly been taken down, but not before fans received a peek at a cut Metal Sonic and Eggman moment that may reveal where the franchise is heading next in ...