According to van Beek, Aloy's model was brought over from Forbidden West, and lighting, skin tones and hair shaders have been reworked to match Zero Dawn's atmosphere. The dev also points out that the PS4 image shown below has motion blur turned off, resulting in the slight blurring present.

Many gamers haven't warmed up to the idea of a Horizon Zero Dawn remaster, but that should change now that the details have been revealed.

Horizon Zero Dawn will soon be released in a remastered edition, and now a dev is chiming in on what improvements were made.