Pretty cool. I actually discovered this 'cause a disqus user has this as an avatar, but with saturated colors. Luckily he/she found your original version!
Just to point something out, the weird thing that jumped out at me was Skull Kid's left leg, or the leg on the right side of the painting. It just looks off to me. I don't know if it's the shading or something in the way you drew it, but it just doesn't look quite right with the rest of him. One thing I think it may be is the shoe(it's too small). Anyway, seems like you moved on from this one long ago. Just thought I'd give my two cents.