Love the concept and interpretation of theme. Platform and control scheme combo is perfect.
Maybe could be a little more clear that the coins are meant to go into the top of the upgrades, we put ours right in the corner out of the way and it ended up being useless. I do notice the funnel element built into the sprite but maybe that aspect could be accentuated more?
I think there is an issue with the fact you have to pay for upgrades using specific items. If you just changed upgrades to cost e.g $150 rather than 25 gold coins specifically it would get rid of a lot of weird edge cases where you paint yourself into a corner with the order or way you bought things. You'd lose that strict progression from one item to the next, but most incremental games just solve this by having each new item cost an order of magnitude more than the previous, making it difficult to sequence break.
Really enjoy the way you build up from copper coins to precious gem encrusted jewelry and golden chalices.
Overall definitely feel a smoother and more fleshed out version of this game could be a lot of fun.