Okay, so this is a pretty well made game however it suffers from a fundamental flaw in design, namely that a game should always be made with reducing the amount of forced time that a player is unable to do something, especially when it is much rarer for an enemy to not be able to move than a player. On one memorable battle, I had 24 health and brought a fox down to 2 health, but then was unable to make any kind of move for so many turns that my health was brought down from 24 to 4, solely because I was unable to do anything.
That's poor design, no two ways about it. One way you could implement a fix is by allowing players sacrifice a turn to throw their card at the enemy, thereby doing a paltry amount of damage, or take a cue from different solitaire modes and make matching or alternating suits and/or numbers do something. Or even take a fundamental part from solitaire and allow draws to affect the cards on the board rather than making up a hand mechanic that just makes the game worse.
Regardless, this game has a lot of potential it just won't be popular if players are consistently punished for the lack of anything they're able to do in a long stretch of turns.