Problem is shoulders, they are dislocating.
Try for yourself to make same frames in real life.
And whatch how yours shoulders move
they shouldnt rotate, yes they can move 1 pixel to side, but not to up, down or rotate, cuz he isnt streching his shoulders, maybe arms lower part, but no other
part.
Also, he looks unnatural now, of course its hard for your skills to make his body move to make it more realistic.
BTW is his last frames, where that yellow thing appears, its that like little blast? If yes, then coat should move a bit.
His legs doesnt look good when he is waving like that.
He should stand hard, like samurai with his sword, like karate fighter, like a rock.
Now he is standing like "after yellow blast I will fly away"
later I will edit your sprites and show how I wanned to make

overall is good, but you should work on legs a bit, cuz now its like butt form a front, its like his a** facing us.