All and all it is not bad.

I am in a 2D animation class right now and just finished the walk and run cycle. I do not have a place to put them to show you but I see a few problem areas and by no means am I an expert. Number one is hip and shoulder rotation. Here is a very quick figure of what I meen. The hips go up and the shoulders go down. A walk is a controlled fall. Maybe add a Slight forward lean. The other thing is the foot motion. Your feet do not travel in a parrallel path. The swing around your planted foot. That is also in the diagram. Try to walk keaping your feet in a parrallel motion. You will instantly notice it seems wierd.

I hope this helps.

One more thing. You have his arms swinging in sink with his legs. They should be opposite. When his right leg is coming forward his right arm should be swinging back. It is a counter balance thing.