If you thought CryEngine looked good, or that a modified Skyrim could look even better, well you ain't seen nothing yet. Unreal Engine 4 has been detailed beautifully in some fan-made videos that we've linked below.
You can pick your jaw off the ground at any moment now. When I first saw the very top video, the one with the snow and trees, I showed it to my nephew and said "check out this video of snow using a GoPro" and he said it looked great. When I said it was powered by Unreal Engine 4, he was just completely blown away, as was I.