Wow! This game has so much juice for a jam entry, I can't believe it. I loved the art style and the visual fidelity of the UI interactions. Super important for a card based RPG. It did take me a little while to get to grips with the various mechanics (health, initiative, damage, cooldowns) but once I got into it, I felt like the combat encounters were nicely balanced with a lot of diversity, which is impressive in its own right.
I did find the UX a little confusing, finding myself wanting to drag cards onto enemies but then having to target them afterward. The "skip turn" hit area could definitely have been the whole candle. Little things like that were marginally disruptive, but I suppose worth mentioning given how polished the rest of the game is.
I felt like the game was maybe a little longer than I expected (brevity in a jam entry is appreciated), not too overboard but I definitely felt like things were dragging slightly towards the end. I understand there were many more card variations than I saw, so perhaps that would have changed things up for me.
I like the idea of endless gameplay. NG+ is a great idea, though I think a little "thanks for playing" or similar would have been great after the boss to give the player permission to exit knowing they experienced all the content.
Overall, still, this an immensely impressive effort for a jam game, and I really appreciated you sharing it with us. Best of luck with your results!