Some things on your big guy:
-He seems to hit the ground, bounce up, he reaches his peak, THEN his legs kick up. If anything the last 2 motions should be at once
-Seems pretty heavy to be bouncing around like that!
-The most important thing about animation is that motion starts out slow, speeds up, then slows down again. || | | | | | || if that makes sense? For example, when he falls over, he should start out slowly leaning back, then speed up as he falls over because of momentum
-Sometimes less is more; you don't need to draw out every frame in his fall. Cut some out and itll appear faster! Also subtle bouncing/sliding can go a long way.
In my edit all i pretty much did is move a few pixels around and cut out frames. Your key frames were well drawn, just some timing issues which are easily fixed
. For such a big guy, it might be fun to have dust/sparks/etc fly out when he lands, but its important to have the initial frames done before that! Also.. the rocket launcher, when hes down on the ground, seems to be about 2 inches thick. Is that intentional?