I was only able to play about 10 or so minutes during my break but honestly for a solo dev its quite impressive. The 3d environment, battle systems and sizable amount of cards seems like it would've been a large undertaking. I'll admit I was a bit overwhelmed by the sheer amount of card options dumped into your lap but I'd imagine you could smooth that out if you ever went past the prototype stage.
Wish I had more time to give it more of a go but I really appreciate you sharing it and hope you keep up the great work - really gives me a lot to think about and look up to as I work on my game.
Cheers!