Great concept and execution...
but the difficulty curve is a vertical line.
My suggestions: add 2 and 1 star battles, and show all cards that opponents use, not just their reaction cards. They are using real cards too, after all.
edit: starting the game with some block cards would be nice too.
edit 2: another idea! maybe limit the enemy count for battles, the most unfair battles for me seem to be the ones with a metric heck ton of enemies and the ones with multiple elites.
edit 3: Oh and 2 other things, please make us be able to walk over hearts without having to pick them up (for example in case we want to save it for later); and can some of the enemies please chill with the counters?
Well, for me it's the opposite. I can reliably kill the first few enemies and then on the second floor before I know it I'm quite literally fighting 15 worms and one of my full health characters died on the first enemy turn. Seriously though, the floors go from having to fight 5 ⭐ battles at most to having to fight like,,, 8 ⭐ battles on average.