Yep, a vast majority of my time was used to create the cards mechanics, illustrations and the AI so that didn't leave a lot of time for user friendliness. Damage calculation is one of the less-explained mechanics, my first update will focus on creating a good tutorial, improving the general layout and readability, and showing in more detail what is inflicted where 🙂
Basically, if you attack unopposed (no opponent card directly in front of your card), your card's attack value is inflicted as damage to your opponent's health. If two cards battle, they simultaneously inflict their attack value at the other's health. A superFast card strikes first if the opponent is not superFast. If your card is Piercing, excess killing damage is dealt to the opponent (regardless of whose turn it is).
Thanks for your feedback!