Thank you!
That's a good point about the sword upgrade, yes there are two slash upgrades and you need the first one in order to use the second. I will be sure to fix that later. There is also an upgrade that allows you to use the sword in the air, which is accidentally required to defeat the boss. The boss was implemented near the end of the jam so I didn't have a lot of time to make him a little better.
Visuals for hitting enemies was something I thought about but forgot to implement, you can look forward to that being added later! Sorry it wasn't there, it should have been in this version. Enemies were implemented fairly late as well, I spent most of my time just building the world, so you can probably tell that they need some work!
I agree that there should be more connections between zones, I will work on that as well.
Thank you very much for your feedback!