So I've been following Hisashi Eguchi on Twitter. No, not Hisashi Eguchi (江口寿史), famous manga artist, but Hisashi Eguchi (江口寿志), the prolific animator credited as "Chief Key Animator" in Sonic CD's opening and ending. At the time I found him (I had been mistakenly following the other Eguchi for quite a while) I thought it might be cool to ask him about Sonic CD, but he's done so much work related to other stuff, and doesn't seem very active on Twitter, and I didn't want him to get fan-shy, so I never did. But, finally, he posted some Sonic drawings anyway! Check it:
More than anything, these pictures make me crave a new Sonic anime. I want to see how it would be done in today's environment, now that SEGA's toes have been dipped into the pool of Japanese animation for years. (SEGA Hard Girls was awesome) Honestly, I've always felt that Sonic's design let itself way better to the bubbly, floaty stylings of the East (Sonic X isn't an incredible example) way more than it did to anything in the English-speaking world.
A manga would be nice, too, but I'd really want that raw movement to showcase Sonic's speed. It's not like SEGA doesn't already own an animation studio, so what's the hold up? Kids would go nuts for it.
Unfortunately it's all hand written so you know, not good chances (and a lot of it is cropped out). The one arrow pointing at Sonic while running says that these are his quills, but to "think of it as his hair." The rest of what I can make sense of is all about what color things are and I'll bet there isn't much more to any of it than that. Edit: No wait, some of it is about proportions and little detail notes ("this is his tail," "shoes don't have any treads," etc). It's not really interesting, just reducing ambiguity for other artists working on the project.
Weirdly, the tweet with Sonic smoking was removed, but the image is still up (since that link I posted works). Somebody left a comment (not sure if it was a joke) saying Sonic should not be smoking, I wonder if that had anything to do with it.
Something about that Eggman art just occured to me, which even shows up in the "bad ending" cinematic. His moustache resembles what it will eventually become Adventure-onward.
The relative crudeness here really does suggest that the animated segments were one of the first things started in Sonic CD's development. The peg-like fingers and graven smirk are particularly notable.