Really great and extremely enjoyable game! Boss fights are always a really nice challenge, and your game made it a really well challenge especially. The lighting and the polishing is just done so well!
The gameplay is a simple but nice mechanic. I ended up also having to upgrade everything of mine to beat the boss...(Let's see if there could be a player who beat it with nothing upgraded soon haha) overall really enjoyable!
One small suggestion is to probably enhance the ui upgrade menu & fonts a bit. I understand that in a jam, the time rush & other factors makes the things a bit difficult to complete, but It would be nice to see the upgrade menu have some nice fonts & polishing. However, the upgrade menu itself is really well created!
Great job!