I definitely think that the head should move in some way. it seems very static and the way it's so immobile looks incredibly boring right now.
it's hard to do a walk cycle from this angle because the form isn't instantly recognizable as human. because of that i hink that you might want to exaggerate things, especially in the legs and the feet.
i think that more frames would help as well. it would give you an oppurtunity for a smoother and more subtle animaton.
don't know what else to say right now. i'm know there's definitely more but i'm having a hard time putting it into words. other people around here are a lot better than i am. good luck.