The front animation looks good, but I'm guessing you are having trouble on the side animation because of where the arms are in the middle frame or stationary position. That is you have little room to sway the arm backward and a lot of space towards the front. Thus, considering that every frame is at the same speed, the arms are moving faster when going forward then backward. Thus make sure the amount of movement of arm is around the same for each frame, this should make the animation smoother. Also what bugguy said, maybe a bigger chin on the side. I really like btw the shiny look on his head.