Really nice entry. There are few things I would sugggest for even better experience, but all you have is very solid for game jam entry! Would be great to see some basic visualization of the attacks/heals/buffs/debuffs, as you have quite nice system build, sometimes it is harder to see the impact of your card decisions since the change is visible just in the numbers and you can easily miss that. Also the UI might get bit more care, I mean I was able to get into it really fast, and that is good, but at first sight, there are quite lot of numbers on the screen and I had to focus what is what at first. And not sure if that wasn´t just problem on my end, but the music is not set for looping? So it ended in the middle of the battle and for the rest of the fight there was a silence.
But overall you did amazing job for the timeframe you had! The art is also great and with little tweaks this could be a base for a great card game! Great job and thank you for this experience!