This game is really addicting. I love some of the "broken combos" you can make with some of the cards, like using the card to multiply the value of coins and then immediately playing the card to collect all the coins on screen. I could definitely see this being expanded into a full game that would be a lot of fun. And it fits the theme really well too!
A couple of suggestions: 1. It would be nice to have some sort of indicator for when the "value multiplication" effect wears off. For other effects it's easier to tell (like when you start falling faster, or don't move side-to-side as much), but I had a hard time figuring out how long the coin value was multiplied for. 1. I think the card drawing animation could be sped up a bit. The "draw more cards" cards weren't nearly as good as I thought they would be, because playing one basically locks you out from playing any cards for a few seconds. It felt like it would always take just long enough to finish drawing the cards right before I hit the bottom of the pit, thus wasting the card.
Overall great work!