I really dig the art style, reminds me of a Cynthoni thumbnail. The visuals overall were great. I think I crashed the game though by skipping after the end of a round when there was an attack round next.
I'm not sure if it was intentional, but being able to do permanent buffs on cards every round was a really neat idea (if a little broken). But I'm not sure there's any way to lose? The enemy cards don't actually deal any damage.
Overall, this was a great submission. With a bit of touching up in the gameplay department, this could make for an awesome card battler!