Jolly Roger has been doing a fantastic job getting stuff from the Sonic X-treme build that was found to work. Most recently he got the level editor used for the game to run on modern Windows and OpenGL, and he has uploaded a video recorded by Andrew75 demonstrating it running on Windows 7. It still needs a lot of work, as it currently has a lot of bugs and crashing issues, but it’s very impressive how fast Jolly managed to get this to work in this state.
Be sure to visit the thread about what’s being found in this prototype on our forums, as lots of interesting stuff is being found from this version of the game. It’s very exciting as it looks like we’re getting closer and closer to having a build of the game that runs well on modern computers, especially now that it looks like we’ll be able to make our own levels. You should also check out this recently recorded footage of the OpenGL port of the prototype that Jolly Roger is working on.