Prime 2's main objective was shifted to rescuing the Luminoth and fighting off the ing. The main enemy wasn't really the space pirtaes. Yeah it could have sounded better like prime 1's but it seemed like this game wanted the focus to be the ing and dark samus.
Definitely liked that too, although they weren't the main antagonists of this game they had a lot of interesting data on their position between the luminoth and ing.
Now this is from a game I haven't gotten too far in (yet?), and I haven't checked out the rest of the soundtrack on YouTube either. But what I've heard, I love. I really enjoy the style of this soundtrack, and it's very well put together!
When starting the game, it brings you this amazing theme right away, together with an accompanying video created from multiple clips from throughout the game. It's wonderful, it really brings you in the mood to play! ^.^
And then here's the spring theme. It feels so great!
Hm, I'd like to share one more... perhaps one a bit more mysterious? Still though, one can't take away the happiness! This is such a nice tune, also! ^.^