Heya, my audio recording crapped out, sorry about that, but in case you want to see the gameplay anyway:
Some thoughts:
I like the overall idea of the game, to use cards to plan a bit of a math puzzle around how to beat it, which the harder levels show nicely. However, for this to work on a more engaging level, you probably would want to include skills that change the base calculation, be it for healing cards, increasing damage, allowing combos, etc. Otherwise the main strategy is a bit too simple, by only asking the player to balance his initiative around which of his own cards to protect a bit longer.
For that reason the puzzle mode also works a lot better than the free form mode, as random cards just entirely crash the game premise to be able to calculate and plan the strategy. In that mode, you would basically just be playing the exact same strategy for every encounter and either you get the strongest card dealed out or you dont, and there isnt much strategy to be done with that.
As for the UI, the Itch page is massively oversized due to the way the game is implemented. Definitely needs some tinkering, as well as improving readability of every single text. For a start, just put black boxes below all text areas and once you do know how to balance and playtest your game, think about UI/graphics again to make it suit the gameplay. :)