Believe it or not, lowering the resolution is a BIG FPS booster. Recall that these graphics boards are completely limited on pixel count because they are rasterizer based. The resolution also propagates to all of the internal framebuffers (depth, stencil, shadow, render targets, etc..).
The game does look good. And I attribute it to the art direction for sure. It's not doing anything that we haven't seen in some other game.