Muscle deformation seems to be largely down to attention to detail and rigging on the animator's part, rather than hardware grunt. Sure, you need a pretty high polycount in the joints to make the deformations look good, but it's not as far fetched as the hair rendering seen in Uncharted 4's E3 2016 teaser. As for lighting, it could be down to dark conditions lit by a single light source putting the visuals under ideal conditions. Not seeing anything that would be too demanding on PS4 hardware. Unless ND significantly updated their rendering pipeline, global illumination is most likely still baked with light probes anyway. Model quality, yeah, I'll give you that. The subsurface scattering seems top notch, almost too good to be true, but we'll see. I think in cutscenes, the game will look this good, but certainly not in gameplay, just like any real time render, really.