Your background looks kind of awful.
It's a mess and easy to tell how you made it.
By drawing different streaks of color and haphazardly altering them.
I imagine you just got lazy when faced with the prospect of such a large image.
I do the exact same thing though so I don't really have any advice.
Sorry.
I like what you did with the dithering on the man's side;
It looks very stylish.
It's hard to tell which way he is walking.
His right leg (the left one) is pretty well animated except that it stops when stepping.
Watch where the feet are and try to make them move every frame.
Because if this was moving, it would appear that his feet are dragging/sliding on the ground.
His other leg... it's hard to tell what its even doing.
It's like wobbling, then doing a kick.
It should be doing basically what the other leg is doing, except at the opposite time.
Like
Imagine if this was just a gif of his right leg.
The frames are 12345678
You'd want the other leg's animation to be offset by half the animation.
Here's some numerical legs.
12345678
56781234
I don't know how else to explain it.
I hope you understand what I'm trying to say.
That's all my tips/advice.
Hope it helps.