Quite nice, many anatomical errors and problems with the shading, somewhere after the 11th screenshot I started to see the main problems, here's an edit:
[img]http://i.imgur.com/Spp7g.png[/img]
The very first thing that bugged me when I saw your picture was the placement of the ear, the starting of the ear from the button is horizontally aligned with the mouth, and the ending of the ear in the top is horizontally aligned with the eyes.
Another thing which caught my attention was the location of the eye, not much of a problem, but they could be pulled a little more left to make it look better.

I'm not sure what were you going for with the look of the lady, but I presume you wanted to make her the prettiest you could, so what I would suggest making, is perhaps moving the jaw a bit further to the left, making the nose be little more stretched down, and colouring the upper lip darker, as I did in my edit.

Here's another picture, what I wanted to show here is the anatomy of how the face would like with the correct settings.
[img]http://i.imgur.com/WyrQP.png[/img]

Other then that, I would also really want to take notice of the shading, from what I understand, the way you colourized the picture was mainly by adding "random dithering", or placing blocks without an actual need to, so, I think that what you could do, which would make the picture look very much more pleasant, is making the shading very clear, with plain colours and AA(anti aliasing), perhaps even add a few more colours for a better contrast.

You could take my edit as an example of what I tried to explain about the shading and anatomy, although it's really just what you would like to see at the beginning of your art piece and not at the end (as it looks very dirty and unfinished). :P


I hope I could help, and if I didn't explain something very clearly, please say so, I'm a bit in a rush now, so I typed this post quite quickly. =)