Hmm. Calling it Sonic 4? Ballsy move, Sega.
The episode thing is interesting. After all parts are released, will you be able to play through all at once? A Sonic 4 & Knuckles, so to say?
So far, I don't see anything detrimental. I don't mind 2.5D in the least, and as long as there's a spin dash, I don't mind the existence of the homing attack.
Key words: so far. We've been fooled too many times already. The few seconds of NSMBSonic may not represent the whole product. True, Sonic will be the only playable character, but that definition's been spun already. I don't think they're stupid enough to make that mistake again, but don't be surprised in the Werehog shows up.
I'm not asking for a perfect game. I'm asking for a good game. I'm confident it can be done. The question is if Sonic Team are the ones that can do it. Prove my doubts wrong, ST. I double dog dare you.