hey
You should tone the leg further back down a shade (so to the arm) to give a better illusion of depth. Also I think you certainly need some more intermediate keyframes, as it looks quite jumpy.
As far as the actual animation movements and such go, I think they are fine.
Hmm, your shading looks to lack any great form or depth, and the clothing looks rather stiff (maybe more intermediate keyframes would help this, but the clothing still lacks any folds and such). Even if you do want a rather light sorta shading style, I think you still need to shade the key forms and also define the folds and such of the cloths.
But yea, you seem to have highlights on the front of the pants which seems to indicate the lightsource is coming from the front. Although this would mean the lightsource flips when ya character flips the other way, and even so the back seems to bright if the lightsource was from the front, hehe.
I might try and edit or something anyhows later.
edit
,

and

Well firstly I done this edit, I tried to better define the lighting, slightly changed the palette and refined the form of some things and also brang the head forward a bit. Then I thought it really lacked style and was a bit messy or whatever and made the other edit. Hmm, well I don't think I captured the light style shading of your sprites, but you could shade it in heaps and heaps of different ways and mine is certainly not the only way to go.
Anyhows I hope ya find them useful.
cyas