A lot of it does have to do with the art-style - which is insanely good here. The various weather effects, the water, the fire, the lighting, the textures, the obsessive amounts of detail, the varied/interesting locations and the animations are all top shelf. Seriously, I could write a whole essay on why this game looks stunning and is one of the prettiest games I've ever played, but I think you just have to paly it yourself to truly understand why it looks so damn impressive. A lot of the little things in the game add up. It's the complete package.