Board Thread:General Discussion/@comment-679780-20160723045230/@comment-6858788-20160726202909

Sonic CD and Sonic 2? Canonically, that's an odd case. They are both sequels to Sonic 1. There were two directors for Sonic 1 that split. One moved to the US to make Sonic 2, while the other stayed in Japan and made CD.

However, I personally think that CD takes place after Sonic 2. Tails appears in CD, but only in minor cameos. However, he IS playable in the rerelease.