"Hold up, 60fps?," you might be asking. Yes, Sonic Adventure was originally rendered at a higher frame-rate than it ended up being. The earliest footage of the game, shown at the Tokyo International Forum public unveiling in August of 1998, had shown the game to run at that frame-rate. As we can see from the footage of the unveiling seen in the one-off VHS magazine Fuse, we can clearly see how unbelievably fluid the game's motion is at this game's prototypical stage. Or was, I should say. If you guys would see it in action, I think you’ll get a kick out of it.
This early prototype footage exhibits the game originally ran at 60FPS, the level highlighting the game, we see, is Speed Highway. It looks particularly impressive given the time this game was unveiled. Its really a shame they had to had the drop the frame-rate down to 30 for the final Dreamcast version.
What's interesting to note is that the AutoDemo isn't necessarily running at a much higher frame-rate than the final or the Forum build. So by that point, the frame-rate had already been dropped by the time the demo was made. Another interesting tidbit, if you noticed even Sonic's jump momentum seems different when he bounces on those enemies on Speed Highway.
Honestly, I wondered if this was a whole other game altogether. The game's original frame-rate at this stage of development makes it look more polished compared the final version. While the rest of the footage around the Speed Highway stage is less than 60FPS, I believe that that footage was actually edited deliberately to reduce the fluidity of the motion. Why that's the case, who knows.
But yeah, Sonic Adventure. What a time to be nine years old and seeing a 3D Sonic game in action on then-powerful hardware. Good times.