Really high quality entry!! Loved the look and feel of it. Made it to round 11 before the creature claimed me, I think I could have kept going but I just ran out of possible upgrades. Really enjoyed how flipping coins and buying items used the same resource, made me consider my choices when buying and betting since higher odds of winning this round translates to less buying power for the shop, and vicea versa. Great work overall!
My suggestion for an item would be "flipping tails gives +1 value to all heads coins this round" and potentially adding purchasable extra coin slots