Ye got me hooked man. There isn’t a single part of the game I’m not looking forward to.
The checkmark notification is indeed for lunch with Yon and Swolis. Once unlocked it will play after each dialogue action taken to let you know how to end the conversation again and again.
I for one like the card battle system. While it is confusing to figure out once I had done so I was able to win the turnip fight efficiently. The only thing I’d recommend would be clear dividing lines for where to put the cards to attack what sides, and perhaps the ability to meld cards to clear up the battleboard when there’ll be a lot of cards on the field. If you were to overhaul it I’d suggest making it a single lane and removing the overwhelm mechanic, making it so both sides attacks hit each others defenses every time, though the lane mechanic could still work in the context of multiple enemies.