That Uncharted 4 footage looks incredible, no doubt. But, frankly, I'm not seeing this massive difference some of you are alluding to.
IF this is actually a Nathan Drake model that will be in-game (I have so many doubts about that demo ND showed), there is indeed massive gap between the quality of the model and any of the ones I've seen in Unity in HQ images.
There's just an attention to detail so astonishing that the only way to illustrate how large the gap is is to just grab onto all the minutiae to compare.
One of the most immediate differences is the insane gap between the (apparent) subsurface scattering on ND's skin and what's going out with the skin of the characters in AC Unity. Look at the way the lighting in the scene accurately penetrates the skin and reflects how the translucency of skin would look in displaying veins, for example.
Then compare the admittedly quite impressive facial animations of AC Unity with the increase detailed Drake's face has when his similarly impressive facial animations are put into action. There's just an incomprehensibly complex set of facial muscles being utilized to warp the skin and give it appropriate contour and texture.
Then there's the simple geometry on display. Nathan Drake's character model quite clearly contains a hugely increased amount of geometry over comparable Unity characters. You can make out the distinct polygon edges on the Unity characters outfits and body - around the hood, around facial contours (look at the lips in the photo of the hooded AC unity image), around everything if you analyze the image. You can make out some of that on Drake, but it's much harder and far more subtle. His arms have it a bit and a few other places.
And then forget about the hair. AC Unity actually has really nice hair at times, that one lady's hair is extremely impressive. But when you compare the technical aspects on what is going on in Drake's hair and stubble, it's hard to articulate precisely how big the leap here is. You can literally follow every individual strand of hair and piece of protruding chin hair. There is so much going on in the hair alone one could write a book about it.
The gap is truly insanely huge. You might casually look at the photo and say 'it's not that big really', but with any analysis of its technical fortitude the argument would fall apart.
Which is why I do not believe Uncharted 4 is going to look like that on PS4. Even in the off screen TV image, which is horrible way to compare anything, you can check out the hair alongside his ear. It's a gigantic drop from what was in this U4 video.