Not bad! You should check out www.pixeljoint.com for some good pixel comments and help. I find viewing others work is the best way to learn.
The only two things that really bother me about these are:
1. The way the feet both face outward in the same way and
2. The particularly dark colour scheme.
The characters also seem a little boring, but you show much pixel skill in these few pieces, keep it up - and check out that site!
'oh yeah? he's thrown a kettle over a pub, what have you done?'
As far as I'm concerned, istvan is definative authority on pixel art, I'd bow to him whilst accepting his advice. Be sure not to let his shadow touch you.
Steve Zissou: Anne-Marie, do all the interns get Glocks?