In the Youtube video they also seem to use a trick of defocussing the real objects in the background when their rendered foreground objects are in focus. You can see that most clearly with the planets. I think they have a macro lens on the camera to achieve this effect and I suspect that it would not be nearly so dramatic if you were to experience it with the naked eye.
As far as I know, and I was pretty deep into this at one point, metallic requires black and without it you cannot achieve any sort of luster-like effects.
See the section labeled "See-through AR == additive blending only".