It's a pretty cool concept. I being the button-mashing person that I am did end up clicking random cards. But I as I played I got the hang of it and used my brain to strategise. It's pretty neat. I love that you included a web-gl version. Performance is spot on and runs well on almost everything.
Suggestion :
I mirror what Okizeme has to say but I haven't tested on mobile. It just needs some additions like a battle deck, Special moves, something to stun the enemies. Also, this may be a technical limitation but the players just going through each other at times does slightly take away from the experience.
Overall, love the concept. I haven't encountered any bugs so your safe for now. So thanks for the game and peace.