I like the concept, the control are a little underwhelming and don't feel super impactful, I think some sound effects could be nice too. That can be easily fixed with shorter animation for the jab for instance and a bit of screen shake and knowback when hit.
There is a very nice talk about it called "Juice it or lose it" on youtube if you're looking for some simple ways to add that extra punch. (hope I'm not coming off to harsh, I like the game, it just need that extra polish to make it pop)
Otherwise, very original, the chaos element is definitely there when multiple enemies start appearing and fighting each other and keyboard mashing is always fun!