I LOVED this game. Might be my favorite entry so far. Having different actions cost you more turns fits the feeling of "generic big boss battle" very well, and was an inspired touch. The game is quite pretty and polished, enough so that I played it multiple times. You guys did a really good job.
This would be the part where I would offer some constructive criticism on how the game could be improved, but not much sticks out. Especially in the context of a game jam. I suppose some visual feedback of how many turns you're inactive for would be nice. It wouldn't change anything mechanically, but I think it would make what's happening easier to understand, make it easier to keep track of how many more hits you're about to take, and give some tension as your waiting for that number to hit zero so you can act again.