This is awesome.
I did notice knuckles's glide is weird when starting to glide above the screen, but really in the final he probably wouldn't start gliding when off screen.
As far as performance goes my framerate never dropped below 57 FPS. (in windowed mode) My CPU usage bounced anywhere from 8-76% With it normally being between 20-45% Memory usage stayed at ~380MB.
CPU: AMD 3500+ 2.2GHz
RAM: 1GB DDR-400
Video: 512MB Geforce 7900 GTO
OS: Windows XP
Since this is running perfectly fine on this computer I think your recommended system specifications could be lowered.
Edit- Another thing to note going back up the S tube and then coming back out is way too fast. It seemed in Sonic 2 especially if you were holding left it would take quite a bit longer to slow down and you wouldn't be quite as fast.
I know it's a tech demo, but hey these things need to be known.
Edit 2 - I noticed some people having trouble with full screen mode so I loaded up all three versions and they load fine for me at full screen and switching to windowed and back to fullscreen.
My default resolution is 1440*900 and switching to whatever resolution fullscreen uses was flawless.
One other thing I noticed in 4X mode when running up the ramp and you jump Sonic can clip right through the 1.
This post has been edited by Skaarg: 15 September 2008 - 09:52 PM