I appear to become invincible after dying. I died in the final phase, hit retry, and the boss just couldn't damage me anymore. I'm not sure what happened there. Maybe the player's hitbox didn't activate properly? I would consider the player and boss being a different color from the background, but the way it is now isn't too bad. Also, I have to agree that the boss feels pretty spongey and could do with a slight nerf to his health. Still, I liked it for what it is. Good work