Well he's at it again! (Maybe we need a consolidated thread for all these ) I'm really excited to see this, I'm one of the few that actually really enjoys 3D Blast. I have both Genesis and Saturn versions, with the Saturn being my favorite.
He also revealed a Sonic R prototype I was surprised that split screen was planned for Sonic 3D Blast I wonder if he has a build of the saturn version or some ex employee? That would prove to be interesting I know a prototype of 3d blast of saturn (tech demo) has already been released quite some time ago, but the ones he has are super early in development.
You can easily reach out to him @jontt on Twitter. He's already mentioned wanting to share the Mickey Mania 2 ROM, so the same might apply to the other protos. Hopefully he's not getting pummeled by collectors trying to buy the things off of him.
These prototypes (along with footage of others uploaded to the same YouTube channel) are from the personal archive of Jon Burton, who is the founder and lead programmer at Traveller's Tales. Considering that his company had a policy - back then, at least - of developing new engine technology from scratch for each project, it doesn't surprise me that he took enough pride in his work to keep copies of early builds, especially in their initial tech demo forms. However, I'm also predicting that soon he'll find himself swamped with offers from collectors wanting to buy these so they can be given wider distribution, since I doubt he's going to be sharing playable code in a hurry... P.S. I was expecting media from Sonic 3D to surface, but it's amazing that we didn't know sooner about the planned multiplayer feature!
I was thinking that but it probably would have restricted view of the course as well. Great to see this. The multi player would have been a neat feature and would would have required some programming tricks to get all that on screen at a decent pace I would imagine.