As a quick follow up, after immediately caving and playing through the demo, it's obvious that they are skipping over bits and changing around where things are just to give you a taste of how the exploration works and (briefly) how Nemesis will. It doesn't show anything we haven't seen a thousand times in trailer (except in the advertisement that follows the end of the demo).
Zombies seem tougher to dismember than in RE2, maybe just tougher in general. Plays basically like RE2, the biggest difference so far being that weapons like grenades and the knife are now bound to a weapon slot, rather than being a sub-weapon. The inventory management and map system is basically identical. The dodge is not easy to pull off, managed to get one or two perfect ones in, but got chomped by zambies quite a bit and was needing to heal regularly.
In conclusion, be excited. The demo area is very contained, a few streets and like three two-room buildings, and it took 30 minutes to explore as much as I could and clear out every area of items.
Nemesis is going to be ROUGH. Hoo boy.