Alpha-blending is easy because, again, it is a set of sorted layers. The only real geometry is some crinkly concentric spheres. I wouldn’t necessarily hand-wave Silent Hill 2 levels of subtlety, with one static moment, but even uniform fog would be sliced-up along with everything else.
Reflections are handled as cutouts with stuff behind them. That part is a natural consequence of their focus on lightfield photography, but it could be faked somewhat directly by rendering. Or you could transmit environment maps and blend between those. Just remember the idea is to be orders of magnitude more efficient than rendering everything normally.