My favorite track from Prime would be the one that plays when you get into the depths of Phendrana Drifts
Also I just imagined a sort of BEHIND THE SCENES thing for this RP. Like what if this RP was a TV Show. How would the characters converse with each other off set? Interesting thing to think about.
The music in Prime had that sort of atmosphere. Like you're literally alone on a planet. Which is what most Metroid games are good at simulating. A adventure where you are mostly alone. That's what I liked about Prime 1. It felt like it stuck to the formula more. I still like Prime 2, 3, and Other M. I just think they have too much social interaction.
My favorite Metroid theme aside from Phendrana Drifts (depths)
The Maridia theme is just so... eerie.
It makes me imagine literally sitting in a blank glass case that is sinking into the darkest depths of the ocean of an unknown planet. Many alien creatures just floating around you in the distance.