The combat button spends your money even after you've bought combat. I bought both the stick and the sword and refreshed the page, now I can't get the combat animation to play. These are just a couple things to look into.
Hey, I'm very excited about this! I found your game from a comment you made on mine. I'm wondering if I inspired you to make an idle game? I'm looking forward to updates on this one!
Spells are overpowered for their price, there should be a spell tree, where you buy weaker spells in order to purchase stronger ones. Maybe you have to buy the zombie slash before you can buy Zombie call, for instance. I was able to be the game by going into the final level with Rage, and pressing D over and over.
Fixed!