A smooth, flowing experience.
I appreciate having zero cooldown on attacks. It was empowering.
A small nitpick on visual design, though the impact was so small it really doesn’t matter: the only times I took damage was when I misread the enemy projectile as my own attack’s splash/burst, especially the red ones.
I can’t really tell these two apart when there’s several other things happening on screen.
If either the fireworks burst effect or the enemy attack sprite could have a different color and shape (something the player can tell apart by its silhouette without looking directly at it), it would undo this. Enemy attacks could be more bolt-shaped or spikes. Or the player’s attack could burst into stars and/or stripes.