If you did not see the desperate, red banner of attention at TSSZ already, Sonic 2 HD, the project spearheaded by members at the Sonic Retro community, have released the first, playable demo of the game. Personally, I cannot play it myself, as the game absolutely munched every last bit of my RAM (and then some), but if you manage to get it running smoothly, I heard it is a nice showcase of their physics engine and the artwork, especially the fluid animations.  I also heard that it is fun distraction at work.  Take your pick. 

Head on over to Sonic Retro, download the demo, and comment!