There are a lot of extraneous animations that makes the gameplay seem a lot slower, I'd suggest either removing them or providing an option to speed through them or not display them.
Instead of the "dagagfdag... gdfasgdfgh" for getting knocked out, I think it'd look better if you used "urgh" or "ugh" or somethin to that degree, the "sdafdsa...gfbgfbd" kinda ruins the moment (but that might just be me)
I'd just like to mention, Armorgames people also complain about the lagging, so it's not only kongregate, but armorgames as well, I'm too lazy to get into an extensive search for this game on other sites and their comments.
It slows down A LOT in firefox, when the ability with the fist and skull icon gets used, I don't know which browser you're using, but firefox isn't handling it very well.
Do not betray such importance to this. Improve everything and enjoy the game. :)