My complaint is that the render looks like it wasn't cut out very well. There is a thin white line around Pikachu that looks a bit unatural. I have that problem with my renders sometimes. I guess that you can't help it sometimes...
It's decent, but I don't like the white pixels that were from bad rendering with MS Paint. Also, the way the rainbow comes out of the tail bothers me a bit... (5/10)
10/10. I simply assumed that the :ganondorf: in your picture was supposed to look just a little grungy, and it looks great! Also, the SB chat is super-funny!