All good, thanks for fantastic game! The only balance recomendation I can give is adding at least 1 heal card for every character. I was going around testing new card added in upgrade and I could not survive long enough without it. (You can add card library later)
UI slightly breakes once you get around 15 cards in anchor with Meissa and it becomes impossible to check what each card does. You can make that card that is chosen goes on first layer and will be visible with it effects. Cards in hand can work similarly.
Additional problem is, I cannot really read small text under card effects. You can probably add zoom on right mouse button to make it visible. (just open big immage of the card on the side of the screen)
I also think many people become disencoraged while learning how to play. I recomend properly explaining what ancor card does cause it got me confused for a few games.
Overall great work, I hope my negative critique haven`t discouraged you.