This is actually awesome, took a minute to figure out but it was really cool! The vibe is excellent, the shaders are all impressive, especially the card dissolve. The dissolve button lighting up when dragging a card over it is really pretty too! I don't really have criticism on the gameplay as it was solid, would of been nice to have feedback when dragging cards and placing them as it took a while to figure out you could drag them. All the cards seemed pretty neat, every one of them felt pretty useful and always felt cool to use at the right time! I think I broke the game slightly, I used the card that allows you to destroy a seal and I used it on the boss, then the next boss counter didn't increase ever again o.o
Overall an addicting game that I enjoyed a lot, props on getting a working leaderboard as well!