The shading on the shirt could be simplified a bit, similar to how you've shaded the hair, and the dithering on the stomach could probably be reduced as well. Nice stuff, though.
The face, hair, and abdomen look great, but the shirt is full of solo pixels and looks very noisy. Your AA also feels inconsistent, you have overdone AA in some areas, great AA in some others, and none in the rest.
...oh my...
As for actual feedback, your shading seems a bit inconsistent. The disembodied hand, face, hearts and PAUSE icon all have a somewhat cartoony, cel-shaded look, but the shirt and chest are incredibly dithery.