My bad, more things to add on after reflecting.
For the music part, I think it's less of a music choice and more of a playstyle discrepancy. I played my last few runs in silence and I enjoyed the game even more.
Even though it's supposed to feel chaotic and intense, I tended to play strategically and calmly, almost in a zen-like mode. It's so fun to clear the whole screen or narrowly eliminating danger thanks to something you prepared 5 seconds ago. Reserving good units, eliminating dangerous units asap, keeping easy stuff until they're right next to you and clearing them aside all at once. I can't praise this enough.
I think essentially it's about what your going for. With the complexity of the game I think it fits a more calm/upbeat theme, than if it was simpler with more reactionary gameplay.