Ok there are several issues with this video; the head turn, the body turn, the way it moves too quickly from standing at the side of the house to walking toward the tree... But the worst I think is the switch from the front view face to the 3/4 view face and back. Second is the switch from front view body to profile body, though I think that can potentially be smoothed out by a position adjustment. And the issue of the way the Soft Ninja moves too quickly from the side of the house to the tree, is a pretty easy fix.
So, my biggest concern is the switch from the front view of the face to the 3/4 view of the face. There has to be a way to make this switch smoother. It may require an in between layer - a 5/6 view, if you will - or it may require some deformation of the front and 3/4 view to merge them both. I'll have to see if any tutorials exist on this issue and what the prevailing wisdom is. And then I'll have to decide which is easiest.
BTW: in case you are wondering if I'll ever actually get to animating the real Soft Ninja I can only say, I hope so.