Played the demo.
Thoughts:
-Amazing graphics
-Gameplay feels more fluid than before
-It is just amazing.
-I love the new segments: harpies, cyclopes, etc.
-Icarus Ascent is hard. But I'm sure it's good when you get used to it.
One main complaint:
-The camera angles. This isn't Uncharted 2. Keep the camera the same, you don't have to zoom in on the back of Kratos' head while he is walking.
I fear they might be making it a tad too cinematic, but it's still awesome.