This is great. I think you've already got the menacing feel with the outlines....but the chainsaw screams 'cliche'...I'd go back to the axe ("Careful with that ax, Eugene"). I see major problems with the shading...there seems to be no real light source, as it'd be sorta impossible for light to be above and under a fold of fat......unless each spot of highlight had its own light.....maybe add some shading in more liberally, too. I also feel that you could clean up the lines a little better, a lot of messiness seems to be sticking out.
But yeah, the chainsaw, your creative decision in the end, but I think it was a turn for the worse. Either way, I can't wait to see this thing done.