Interesting stuff. I wonder how much of the game was actually changed. The only difference I was able to spot right now is the texture of the Bearded Ladies (0:49). Let's hope someone is going to be able to hack the demo.
It's likely something that was changed in the final build. There are quite a few visual changes between the final release and press screenshots. For example:
These zombies' textures look different than they do in the final release. Also the aforementioned green Palethorn. Not sure if we have an online screenshot of that, but he's on the MediEvil Platinum poster.
If I remember correctly, MediEvil 1 had a level model for its title scene. If the developers created the title scene for MediEvil 2 like they did in the first game, it should be explorable. You are talking about this, right?
Edit: I found the model. But this still doesn't really say much, as they could have used some other technique in MediEvil 2.