Ha
So this was cool and I beliece you depicted him just "RIGHT" the ha ha's in the backround was nice and seems to be fitting this was a good "JOKER" in its cartoon form so nice job here, I think some textuture in the hair would be nice, but regardless this was an amazing art piece and just perfect for a comic piece if you decided to make a comic from it, anyways nice work here.
~~THINGS TO IMPROVE ON~~
I think some textuture in the hair would be nice
~X~