My students tell me that you should keep working on it lol

I did record a video of Card Souls but it won't be out for a while and I wanted to give you my thoughts 'cause I thoroughly enjoyed it.

Should you keep working on it? Absolutely! You've got yourself an enjoyable core mechanic and that's a good chunk of the battle.

The limited cards + Stamina made it very frantic when paired with the position based attacks. I had a 'click' moment when playing it where I managed to beat the boss and it all flowed nicely. Exactly what you want from a gameplay mechanic.

If you want to develop this battle system a bit, my biggest complaint was the movement cards. I don't know whether it was my screen (full screened) but moving it to the sides of the screen took extra time that often meant I didn't get there in time. Maybe extend it so that putting it either side of our character does it? Again, could've been me.

The boss also potentially ventured into frustrating territory with the chained healing but that's balance tweaking for you.

If this is stomething you want to keep exploring then bear in mind that I don't think a game of just this would fly. It'd very easily become quite repetitive. It's like Pokemon, you need the wandering around cities to break up the battles.

I recommend taking a look at Hand of Fate 2 for a nice idea of blending together combat mechanics with a card based system. If you don't want to take it further then no worries, I look forward to seeing what you cook up next. :)