Maybe I'll give this a shot. Games that apply: EoSD, PCB, IN, MoF, SA. Not gonna do titles, credits, and such since I hardly pay attention to those anyway.
- Stage 1: EoSD. I like the opening and the trumpet's melody, but the rest is bland enough to (barely) push it below the rest (yeah, it's kinda hard to call this one).
- Stage 1 Boss: IN. Wriggle's theme is so annoying. DHM to Minoriko's theme.
- Stage 2: EoSD. Lunate Elf is too bland on its own, plus it really suffers from EoSD's bad instrumentation.
- Stage 2 Boss: MoF. Hina's theme feels too random in the way its melody progresses.
- Stage 3: IN, because it's vaguely associated with Keine. Keine is associated with history. I'm not fond of history. You do the math.
- Stage 3 Boss: Tie between IN and SA. IN for the reasons above, SA because Yuugi's theme has little substance whatsoever.
- Stage 4: EoSD. Really lackluster melody compared to the rest.
- Stage 4 Boss: PCB. Another tough one, as I've just realized that I somewhat like the Prismriver Sisters' theme, but I don't think I'll end up liking it enough to overtake the rest.
- Stage 5: IN. Two words: ZUN trumpets.
- Stage 5 Boss: EoSD, if only because of the horrible instrumentation.
- Stage 6: PCB. Nothing about it really stands out to me, plus it gives me bad memories of OMGBROKENSTAGESPAM.
- Stage 6 Boss: IN (History of the Moon). That's not to say I hate it at all, just that it barely misses the cut.
- Extra Stage: IN. Annoying trumpets again.
- Extra Stage Boss: MoF. I don't see why everyone likes Native Faith so much. IMO the fast-paced piano at the beginning is cool, but the rest isn't.
Not gonna label one game as having the "worst soundtrack", since it would be wrong for me to condemn whatever awesome songs each game has in the process.
Boss 4: Gah... So hard to choose, all so awesome... I guess I'll go with 3rd eye =/
Wait...what?
I know you're saying they're all awesome, but seriously, 3rd Eye is way too good to be considered here.