Got another chance to play this today, and due to having a bigger HDTV to try it on pretty close up, got more of a chance to really look at the visual style that's going on.
Every time I see GGXS, I am more and more amazed. Looking at it close up today, it almost looks like the characters are drawn in colored pencil in some ways. Edges aren't solid lines - they've got a roughneas to them. Not from aliasing or whatever, but from deliberate stylistic choice. The way clothing pieces or body parts blend together is simply impressive, and there are just so many times that all of those little details make you swear there's no way it can be running 3D character models.
I always fear making statements like this, but taking into account artistic, design, and technological considerations, this has to be one of the most visually impressive game I've ever seen in my life. I have seen it multiple times now, and I still cannot believe that it is a thing that exists.