On the 3rd restart I roughly understood the game mechanics. It was probably just me^^
The background music is atmospheric. I think the art style is great.
I would have liked to swap my cards more often, but that wasn't possible. Even though the intention is that you can't lose, I would still have liked a mode where you actually have to fight for survival.
You could also automatically activate your cards from left to right and then only target the opponent card you want. I like it comfortable^^
Good idea. Nice game.