For a moment, I thought I downloaded the wrong game. It looks very polished and professional. I'm assuming you're on the advanced track.
I'm not familiarized with Deck building games, so I'll apologize in advance if my feedback makes little sense.
1. I wish the cards in my hand had more stats visible, not just HP.
2. The tooltip/dialog when hovering cards were very difficult to read. I have dyslexia and ADHD, so the font choice and the excessive amount of white space threw me off.
3. The cancel function is easy to miss. Frequently I played cards by mistake, because I just wanted to see potential damage.