i like it. i didnt thought i would say it ever but some bloom for the background could add the little extra to the fog in this scene.

rain aint easy to make so it looks good. maybe you will post some video later on as well to show the scene in motion. i am sure this will look even better.

if there is one thing that could be added it would be shadows. maybe you find a way to fake them onto the ground (sprites, models, shader). this would be a great add on.

great work so far, keep it up and keep some shots and videos coming

cheers