The biggest issue right now is a spacing, hands and feet moving erratically and that create blinking effect. if you take two extreme highest points for the hand and create a motion arch (that's what makes animation fluid for the eye) you'll see the jumping off that arch. Spacing should maintained along that arch something like that - just a quick illustration (don't have time for more accurate drawing=):
Actual spaicing between red points could be even (woosh-woosh-woosh=)) or more on the middle and less on the ends of an arch (wwwwooshhhhh-wwwwooshhhh-wwwwooshhhh...) - it's depends on type of run you created (considering figure weight, age, sex etc to make you character) and a style of the image - let say, cartoons have no limits for experimenting, but still follows the motion arch for each moving point of it.=)
Far hand moving on a same orbit with a front one and they just replaced each other for a viewer in extreme points. And again, arms and legs shrinks and grows - try to run it on a slower speed and you'll see what happening.=)Pay attention to the front shoulder, something realy strange happenning to it.
As for the head rotation, here is come edits - arching left-right and left down/up/right down - or whatever you've meant it to move - make a path yourself=) Not nessesery to use all key frames or full rotation - as long as spacing right it could be one turn per two frames cycle.
Ear not in place, it almost hits the eye brow.
