This game has a really cool concept! I love deck builders and trying to find an infinite combo to power up is a really cool idea. I had a loop going that was giving me free block and doubling it, but I think I misclicked somewhere and accidentally destroyed one of the cards.
I think the single thing that would improve this game most is adding sound effects. Just a sound effect when you draw a card or play a card would be huge for the feel. For you next game I'd like to challenge you to try to get sound effects in early even if they're just placeholder beeps and will be replaced later. As you're making a feature if you feel like eventually a sound would go here throw a generic sound in asap. Sound is the biggest bang for your buck when it comes to game feel and is the one thing that will improve how fun your game is the most. A generic sound that isn't perfect is often better than no sound at all, and adding placeholder sounds to be replaced later is much easier to do than trying to totally go back and do all sound implementation at once.
Awesome job!