Really enjoyed the music and the hand-drawn art, the game is also super in-depth. However, the timer feels a bit too fast for the amount of text and mechanics on the cards. I'm sure players will get used to it eventually, but it definitely means a lot of trial and error at first.
Maybe offering fewer upgrades at the start could help. I think having a shop between fights would benefit the game loop, alongside introducing more cards further down the line so we aren't overwhelmed right away.
Nonetheless, good job to everyone on your team.