I only just found out about this, but it looks very interesting. I really like the look of the physics-based combat and the idea of the world being perfectly able to exist without you, and you just interfere wherever you like. Of course, it's one thing to make a Molyneux-like statement like that, and another to deliver on it, so we'll see. The STALKER games gave you a bit of a sense of that, with other people completing your objectives and getting into fights without you being around and I thought it made those games so special.
Unless I missed something, which is quite possible, it seems that they're supposed to release some kind of prelude this month, so we should get a decent look at it soon.