I had to read the comments to figure out how the theme was at all implemented. (To anyone confused, you can buy upgrades that make you drop more money when you die.) I didn't know what the weird "$" thing was but I bought it anyway. I didn't really notice the difference.
To be honest, I found that the gameplay got stale after some time. It was just "kill the monsters, buy upgrades, move on". It felt satisfying when the skellies didn't do any damage to me because of my shield and I could just stand there. Also, when I bought the wand, I dragged it into my weapon slot because I thought that's where it would go, and then I couldn't equip my sword anymore, which make the rest of the game unbeatable (I think).
Overall, I think you could be clearer with how the game is meant to be played and maybe add tooltips to tell the player what each item does. It was certainly an unexpected game to play in a game jam, so well done on that!