The flat colors are subtle gradients, hence the color count. I'm very interested in your process for making this, could you go in some detal? I love the finished piece, ambitious pose that's carried through, some emotion, wonderful. The pixel art technique, besides the odd gradients, is ok. Once we've hopefully helped you remove the gradients and seen that the piece doesn't suffer much for it, we can then see about nitpicks and minor alterations.