Awesome game. It feels pretty similar to other card games like this, but still distinct because of how the deck building works. I also like how the art on the cards matches how the character looks on the corresponding level. And the art in general looks really good. So what if it's AI.
I've only played Amber so far, but balancing seems pretty good and I haven't had any issues so far.
Good luck with development. I'll definitely check out new updates and the other characters.