Cool intro but you should've given an option to press a button to continue because not all people are so fluent in english.
Also you should've set stretching to canvas items. I have 2k monitor and the window was kinda small.
Interesting idea to gather cards by defeating enemies.
For me the game was difficult, couldn't go through B3. Tried 3 times. Don't know how to defeat 2 fairies and mage. All of them cast heal and I dont have enough damage... They had 50-ish hp each(!) in the end... And started to make more armour...
Also got a bug where couldn't apply a skill. Maybe because of several skills activated in the same time. I may messed with repair card that i didnt understand.