Wow, that's a crazy score! My own record was somewhere around 500k I think. And yeah, didn't really take into account that you could get so much hand size that the cards wouldn't fit to the screen anymore. Bummer about that softlock though. It looks like it somehow got stuck to card dragging mode as it's highlighting that one cell but the card is nowhere to be seen.
Thanks for the compliments! I really enjoyed working on this too and it would have been fun to design more crazy powerups and combos but sadly I did hit the 13 kilobyte limit fairly early on and even had to strip off some features to accommodate for mandatory bug fixes.