I'd make the kelp in the background more distinct. Don't know, more specularity? Also, something is bothering me about the lights... yeah, that radial light in the front is too small. I think you should make it more like the whole window is glowing. You should use soft(-er?) shadows on it, definitely. And, yes, create volumetric lights (real or fake) for the headlights. And the ambient light could have more blue. The bottom is excellent now, with a couple of objections. What's that dark thing in the foreground? A ray? And the stones below the kelp should have a different texture, cause mossy rock looks quite unrealistic compared to the green stones in the sand. Great sub.

-- erlik