i personally think that being able to streach out of your comfort zone is an important skill to have, irrelivent of the 'style'.
as for critique, i must admit you havent really followed mirre's style at all. some things to note are
1: the facial features (no white in eyes, noses are visible, ears are large, etc). take note of which features are included and exagerated. the dued with the hammer has large ears, nose, and 2-pixel eyes. your girl has larger eyes, a fatter face, almost invisible ears, no nose, etc...
2: the shading. mirre uses very few colors to shade. it seems to me as she generally uses a close-to-black tone + pure black to ouline, and only 1-2 shades to actually detail. your santa has at least 6 colors on his stomach alone.
3: the outline. mirre uses sel-out, but at a lot lower of a degree then you are. one thing that really doesnt appeal to me about your sprites is the contrasty inconsistancy of the outline because the selout forces it into forms, and then the forms loose shape when the outline gets to light (if im making any sence at all...)
there are other things too, im sure you can pinpoint them yourself.
if i get bored enough, ill try an edit on your girl (she really sticks out [in a bad way] to me)
hope i was some help.