Can't play it, I'm a Macintosh. But I did watch the video. Very pretty, I like how it looks like the old Sonic art come to life complete with sharp edges and airbrushed looking colors.
However, I fear that the game will bring out a lot of bitching towards SEGA. I hope people can just enjoy the fan effort and not turn it into a "LOLZ SEGA failed but this is epic! SEGA should hire fanz!"
Because, to be honest the physics, character designs and stage layouts are 100% SEGA made. Even the art and music which is brand new, is based on existing art and music. Fans just replicated it. They did a great jog in doing so, but in the end its a copy. Just hope fans remember that.