Thank you for playing and for your comments,
I have been informed that Blining at the final boss can "sometimes" end it right away, the area2d is behind obstacles that would prevent dashing but somewhere in the code is a gap that allows it. Tbh not allowing the boss to even attack and single slice your way to victory also works thematicly so I'm not sure it should even be fixed :D
I didn't think of Hyper Light Drifter (HLD right?) but if I had it might have added a clearer visual esthetic to the game. This is why beta tests are important because we can get great ideas :)