I think this piece works quite well - if you were to do more versions of it, I would suggest finding photographs of people, black and white, contrasty images, maybe. Photocopies would work. To really create the sense of multiple, identity-less people, that is. I'd almost like to see floods of the people, maybe from shoulder up, mostly... you might be able to create the illusion of billowing smoke with those fragments of people. Very nice work.