The arms are very jerky and move way too fast. Keep in mind that the arms move at about the same rate as the legs, but in the opposite direction. The general leg movement is also off. They seem to speed up at times, which is not how legs works.

The best way to improve this is by looking at someone walking(even yourself) and trying to emulate that. Carefully study how the limbs move, and you will have a much nicer walk cycle.

The other problem is that your cycle is 6 frames. A walk consists of 4 primary parts, so using 6 frames will create some problems. If you want to go 'retro', just go to a 4-frame walk.

Based upon how far the closest arm reaches beyond his body I would expect to see the further arm reach the same points as well. But I don't see it and the arms do not swing in a mirrored fashion about the body. As in, when one arm reaches out in front of the gut, the other should be extended behind the back.