Awesome work man I love his design really badass!

The character design isn't bad, definitely one of the best madness character redesigns I've seen that aren't from rhyunc, that being said the character suffers because of the poor background, and awkward use of what look to be a transparent brush over him with white (upper body) and red(waist/legs), the "wash" and "halo" are unnecessary and detract from the design a bit, get rid of them. You lose a bit of perspective on the left side of the helmet so watch out for that. The shading currently isn't anything interesting. I'd say go for harsher lighting and greater contrasts. Finally the background: you need to fix it a lot. That big black thing in the background (I'm assuming it's a building) should be solid or at least more solidly colored in than it is. The red and black strokes for the sky are pretty unpleasant to look at and could probably benefit a lot from a more unified method of coloring.
Hope that helped n some capacity, good luck with your art.