Ok, first I think the header needs to be altered to something better, that goes hand in hand with your concept. It kills it.
Second, the harsh shadows. I know it’s tempting to use them hard, black and very big (no bad thinking on this comment please..lol) my young-padawan, but you have to go soft, subtle and small. Less is more.
Third, I would add a bit of texture. Noise could do the job.
Other than that, we are good.