That is a masterpiece, I missed mini metrodivanias that are well designed and everything is perfect. They were common during the flash era with REDDER, Escape From the Underworld, etc.
This is incredibly designed, it is a masterpiece, of course, I got certain upgrades out of order which made my life a lot harder but overall that is amazing and rendered one of the upgrades not that much used but overall that is amazing.
You should finish and polish it and charge for it, that is an incredible game.