Hehe. It's funny to me to see such an incredible piece of art and then see in the caption, "That I did on the weekend.". Very casual like, eh, it's just something I threw down on paper. Very impressive.
background: god, detailed on the left and sloppy on the right, I like that contrast. Batman: not too much mussels, good. Most use WAY too much mussels. Good work on where the lights are coming from, deep shadows giving him a mysterious look. And I like that the bat symbol is not completely visible, looks more realistic. And the smoke looks good, but maybe a little too much if you see the one in the background (behind the water tower. The light on his chest and head, like how it goes out, what pencil did you use to make that happened?