During that first kick, I noticed it was double framed when he delivered the kick, and then single framed after. Try to reverse that so that the actual kick is faster, and the settle after the kick is slower and smoother.
When he's jumping, make sure to extend the leg applying the force. A jump feels much nicer when we can see the leg that pushed off straighten, and then bend as he starts to fall.
As everyone else said, make sure we can really feel his weight. I know he's a stick, but his head and body have to feel like he weighs something. A lot of this you can solve just by translating him up and down much more. Don't be afraid to move him in big arcs like a bouncing ball!
