Wow, I think this has been the best arithmetic game I've played during the jam. I only have two critiques:
1. I can tell that a lot of time was put into the music for this game, and I love how there are different parts that play depending on whether you're in battle, fighting bosses, in the shop, etc. Unfortunately, the loop that plays for the regular battle theme is too short and it gets really repetitive by around stage 15 or so. Everything else music and soundwise is great, but that one loop started driving me crazy after a while. :(
2. The art is super polished, and I really like the animations...but why did you guys go with the hand drawn digits for the cards? Everything else feels so professional, but the cards still look like debug programmer art.
I only point these things out because otherwise it seems like this would be an almost perfect arithmetic game. I spent a lot longer than I would have expected playing it compared to a number of other jam entries, and it was a lot of fun too.