Not gonna lie, I felt a little bit cheated that the upgrades weren't doing much hahaha I spent so long grinding and the only upgrades I could notice did anything were the ones you purchase in the main menu.
Other than that small thing, I think the art is really good, gives me A Link to the past vibes, the one for nintendo switch, that is. The gameplay was smooth and I had no other issue other than the upgrades not working.
Very fun and addictive, good stuff!