This is pretty cool. I like the experimental color choices you're using. I think there is a few issues however.
The first thing I noticed is that the green and the brown hues nearly mix; I think you could raise the saturation a bit on the green to more effectively use color.
Another part that really bugs me is the top right corner of the piece; for one, it is way to straight and angled, which gives is a very pointy effect--maybe round that off a bit. Secondly, I think the intense highlight here is a bit much...I'd at least tone it down to the green hue.
Lastly, I'd like to point out that the last two purple colors before black are nearly identical--personally, I'd make the darkest color a more saturated purple, but that's "what everybody does"
It's really up to you though, just thought I'd point out the lack of contrast between these colors.
Aside from that though, I like the folds you've achieved, and the face is spot on in my book.
Good stuff.
Keep pixelling!
