Crysis on a high-end DX9 PC...

I JUST REALIZED SOMETHING:

I put everything on medium, except I turned shaders to low. The most dramatic thing happened: Lack of foliage, and even worse: lack of swaying foliage.

Yeah, it's for certain -- shaders to a helluva lot.

Is the demo DX10 compatible? Only in DX10 mode do you get full environment destructibility (not just blowing down houses by huffing and puffing).nytrospawn

Yes it is.