And yes, you can complete the game without killing anybody
I actually believe them on that one.
I think they showed rather well with HR that they can make a decent, interactive game world that would work well with a Thief-style game, assuming they're able to ramp up the level size. I'm more concerned about the 'next-gen' features that will no doubt be present, as well as the general art direction. Looks like a console game with way too much shader and filter shit, instead of proper lighting.
Someone should make a Thief-style game with the Stalker engine. That (in-doors) lighting is just so much better than anything else out there.