The character models and visuals are very detailed and very unique in this jam. I like the idea of hitting back enemies into the boss to stun him but I think the control scheme is really holding the game back. The movement is all fine but why would you make the attack button J? it felt extremely unnatural and made moving and attacking extremely difficult. I would suggest just making it the left mouse button or even space bar would be better.
I couldn't really work out how to damage the boss most of the time as sometimes knocking enemies back would ground it but sometimes it wouldn't seem to do anything.
I do like the idea of having different characters to choose from that have their own benefits. It also feels really good to chain hits together on the different enemies.
Cool game, with a bit more polish could be a really good time!