First of all it's amazing how much content you've got in this game. But I've got to say I loved exploring the world but on my first playthrough felt that the main mechanic was stopping me from it by making me constantly go back for weapons and deal with one enemy at the time. I've had much more fun on my second playthrough when I got to the second stage. I ran and dashed through the first one (that was kind of boring), but in the second stage I liked how you've managed to strike the balance of running through the level and having to still fight enemies on occasion because there was to many of them to just run through.
My main problem with the game is that I didn't really understand where are the hitbox borders so I'd sometimes get hit and sometimes not which made it harder to decide which strategy to employ at what time.
But I think that can and will be easily fixed post-jam if you decide to further develop this game (which you should).
Great job!