Personally, I was never a big fan of Soul Reaver. Didn't like the gameply, concept, or idea. And the main character, aside from a seriously cool name, didn't seem to have much developement in my eyes. At anyrate, I felt (after playing the demo some years back) like I wasn't being fair. I played it at a friends house and it seemed rather bland to me, still.
But the way I see it, if you love the demo so much in the areas I didn't...you'll love the game.
Couldn't possibly cost all that much either, could it? And most retailers have that whole "played it? return it!" deal.
I can't seem to think up a good signature.