Solid framework for the game design you're going for. Although it's way too difficult for me. Maybe only dashes should count for overloading, because when I did about 30% damage to the boss with normal attacks, I had to run away for a long time just to cooldown again so I could keep attacking. And by that point the boss was attacking so much I could barely get into range again.
The sound and music was cool though! It seemed like the boss attacks were generating the beats. Nice job on your first game in godot!