This was really fun! I wasn't sure at first what the deck was for, but after a few round I understood that they were permanent upgrades, and the game became really interesting. It's a neat twist on the vampire survivor-like! There might be some cards that make the game really hard (enemy speed increase is devastating); but inversely there are also others that make the player really powerful. It's really exciting to see the same buffs and nerfs getting applied over and over. The only useless ones would be damage increase and enemy health: since they cancel each other out, it's like these cards have no effects.
Anyway, I had a very great time on it! And I also like how the final boss is introduced, really cool presentation. Congrats for making this great game!