yes, i dont think the swings have enough followthrough, actually the whole thing seems kinda silly. perhaps that is what you were going for though? if not though i suggest examining the fundamentals of shortsword fighting, since his technique would have him dead in the sand in moments. actual pixelwork si great as usual, and i like the colors/shading style used.
as technique is conerned, youve actually got a very solid combo with the slash high, back mid, thrust mid, but they dont transition smoothly from one to another, and swordfighting is all about fluidity of motion. Also, since his feet dont move, the very good aggressive combo your are using becomes useless because he is by default defending. If you must keep the feet still, id would suggest slash mid, back mid, thrust low, thrust high, a combo which allows the opponent's guard to flow over you with your slashes to keep his hands out while keeping your other hand free to grapple if necessary before you pin him with the low trust and finish with the high (in simpler terms, you knock his sword away with the first blow, his shield away with the second, pierce his stomach with the third, then ending with a stab to the face or throat).
If you want to keep your aggressive combo, he should take one step with each swing, changing between closed and open every blow to gain ground.
If you want to make the combo more aggressive, i suggest beginning open and going back high, rise, and pass on the right with a back high. its a risky combo but uts fast as anything if you dont drag out the rise and it allows you to move on to the next opponent with your now dying first target keeping enemies off your back as he falls.
