I love when little card games like these are ported to Game Boy, I find it super appealing. The general presentation is nice as well. I'd personally prefer just selecting the boxes with the cursor instead of pressing the tiny button sprites, but as a whole, the presentation and UI feels right at home with this game. You definitely don't need that pop-up message about starting the game at the beginning, I think the menu itself gets the message across well. The use of cat photos also makes for a charming touch.
An altered version of blackjack makes for a fun approach, I quite like this kind of thing. I think there's room to add a little more strategy to this; like how blackjack has aces serving as either 11 or 1, or with the increased odds of 10-value cards. With this one I was typically just staying on 2/3 losing odds, and hitting on 2/3 winning odds. That said, with the jam being about luck, maybe that's the point. Regardless, I did get a little obsessed with it.
The music is great, the title screen theme is a bop.