Heeyy everybody

I took a huge break from pixelling to work on drawing, and upon returning to the medium I found that I forgot a lot of things... Mostly animation, though.
So here I'm starting to animate 8 directions for this little guy:

But before I do the other six, I really want these to run smoothly. This guy is going to be the main character, so I'd really like him to look good.
I can't get his legs to look like they should... I would really appreciate some sort of edit. And I know that the whole body is not moving with the walk, but it is a robot. If you disagree, let me know.
Also, should his right arm move with the walk if his left arm is aiming? Should his left arm recoil slightly even though he's a robot? Should his head move? I know these things would bring the animation to life, but I did have a moving head and he just looked too loose.
I'd also really appreciate some crits on the palette I've got going (Going for a slightly rusty look) and on the character himself, do you think he could be drawn any better. And anything else you think I should know.
Thanks