The more I play the demo, the more I feel like it's a very, very small slice of "transition" gameplay; that is to say, it feels more like the glue you get in most FPS titles that holds larger segments, or set pieces if you will, together.
In short, it doesn't seem like the demo areas are designed with the intention of being on there own; it feels like there's not enough context to provide a proper feel of the game. So, a lot of people who are complaining about the linearity of it -- I suppose they have something there -- but I don't think it's a fault of the game, so much as a fault of taking a slim slice of the game, bringing it outside of context, and saying "Here, have fun."
And the irony of that is that, a lot of us who are not so concerned about outdated visuals or some anachronistic gameplay (which is, obviously, a purposeful design choice in lieu of DN3D and that history), are actually having fun with the thing.
In a sense, I think that bodes extremely well for the final product; if such a demo as this can provide an ounce of fun, you'd think the full game, evaluated from left to right, start to finish, may be exactly what we want out of a sequel to DN3D
Taking a slice of most anything in DN3D which such a small scope would probably yield similar results. Remember, when we all played DN3D, we didn't get a 14 minute demo, we got a third of the game. A game like DN probably requires that to really understand the overall vision.