Couple of updates.
- Classic Sonic will be mute, but shows his personality through his actions.
- Classic physics seem to be back: can roll off a ledge, keeping momentum, without coming to a halt a la Sonic 4; roll into ball as you run by holding down; spindash by holding down+jump.
- Spindash move is also hotkeyed, i.e. there is a button just for spindashing (see 0:25 of second video above).
- Probably known info, but the 3 main eras used for picking games/zones are Genesis, Dreamcast and Modern.
RubyEclipse, of SEGA, at NeoGAF forums:
We've been listening to feedback for longer than you may give us credit for. All that feedback on Sonic 4 - the parts where people wanted Classic Sonic and physics closer to the originals - and now a game shows up with Classic Sonic and physics much closer to the originals. Crazy coincidence, right?
This game has been in development for quite some time. When you play it, I think you'll find that a number of key issues you may have had with physics in Sonic 4 have been completely addressed.