wow.. i love the colors too... not just basic white/black, but multi tonal hair/skin.. awesome man. She aint half bad looking either... keep up the good work man.
Yes indeed OC is fun. That sketch is cool... did you use refs? doesn't seem like so, anyway (well, there are some problems...)
you should correct the kin if you rework that pic.
the tones are very unnatural. The transition from skin color to the cooler color is very sharp and makes it look weird. Also, the skin tone itself could use some work with warmer colors.