One of the points Arkane likes to make is that there is plenty of room for players to be as bloodthirsty - or not - as they wish (anyone else here tried for minimal if not zero kills back in Deus Ex or one of the MGS titles?). By way of showcasing that, they released recently a dual playthrough of a single mission in the game which can be found, probably among other places,
here.
Consider, too, this more recent
Gamespot entry. Granted, there's one problem brought up there that needs to be stomped on, quick, but otherwise it looks like the devs are running hot, straight, and normal.