This is really well done and gives off slay the spire vibes. The only issue i have gameplay wise is that you cant hover over the random runes you gain after each fight to see what they do, which means I wasn't able to properly build up a synergistic deck and just picking random runes instead. Unless its a bug where the hover text didnt appear. I do feel that the UI could be made bigger, the health bars at the top are pretty small and hard to look at.
I did also encounter bugs though, like the game freezing at times and i took multiple copies of a rune if i spam clicked a rune in the rewards screen. It seems that you made your WebGL build compressed, which can lead to issues like the game not being able to run on some web browsers (I couldnt run it on Safari and got an error message shown below). Load times would also be much longer, but that didnt get affected as much since this is only a 2d card game.
You can disable the compression settings here, and I recommend doing this for all unity WebGL games:
File > Build settings > WebGL > Player settings > Publishing settings > Compression format > Disabled
