As a big fan of card games, I enjoyed this a lot! The gameplay has all the mechanics you would expect from a good TCG. The UI is very nice to look at too.
Like others I noticed some performance issues - my CPU fan would become super loud at random points when playing this game. I don't remember this happening with the last version I played (which was 2 demo days ago I think?) so it might have been due to a change since then?
In regards to card balance, at first glance, raw stats seem pretty overpowered. As a wizard I created a 1 cost 11/11 beatstick and then coasted through the rest of the game with that lol. Effects seem to cost a lot more than stats, like a "destroy target minion" card would still cost 7-10 even after spending all my crafting gems but with the same amount of gems you can easily create a 1 cost 11/11. This is pretty different compared to MTG where a "destroy target minion" would typically cost 2-3 mana.