Alright, as you have requested I will critique this, but first I'd like to say anything in this critique is strictly meant to help you and give you advice, and is not meant to be hurtful, rude, or to be taken in any negative way.
I think this is a great piece with lots of originality. I have never seen anything like this and i really like this. I really like the way everything is black and white other than the graffiti on the chair. I think this gives it a really quirky twist as it is on an old fashioned chair.
One way it could be improves is by maybe blurring the back ground out to make the chair the center of focus but that is all really. I hope you take all my comments to good use and maybe take some of it on board.