I heard on the 1up show (from Brian who now works at Insomiac, so that should be reliable ) that the final version of that scene is actually going to have that whole building on fire ... ! Also, he didn't smash that bridge, but actually he grabbed it. You can see that if you look carefully, as you walk through his clutches. Nice detail from the 1up show also was that while playing, Ted Price actually almost died and he would have had to start the demo again as they weren't using any kind of god-mode. And they didn't have a fall-back feed either, like Gears did ...
The Leviathan did a couple of things: punching building parts, swiping the top floors off, and toppling one with bare hands. Still I think what xbd and ignoramus wanted are more obvious destruction and more frantic game pace. Personally, I thought it's a little predictable because everytime I landed on a new place, I get to shoot at the big guy. Would be nice if in some cases, I need to run asap first.
The sense of danger may need to be tuned (Unless James Stevenson already knew where the dangers are and always get to the right place before bad things happen).