Now here is exiting news! Over at Sonic Retro they have aquired the rom Sega used to give to magazines to advertise the game, however just by the video you can see things aren't exactly final! Weird loops and different art abound, including those crazy trees! Compare this demo to say the long lost Sonic 1 Genesis demo that people like to fake. However, this one is indeed real and ready to be dumped to the internet. What will we find? Also earlier versions of Sonic Labyrinth and Tails Adventure are on their way as well.
Follow this thread for more updates.