I only finally played the game recently and then it occured to me to check out the SPC set and hear how the mood-setting music works on its own.  It's dark, haunting, pipe organ-esque stuff with some chorals here and there for good measure.  It seems considerably different from a lot of the stuff one would expect to find on the SNES or even in general.  I imagine that it gets overlooked because the game itself can be off putting and because the music might be too oppressive at times but it sounds to me like this one could be a stand out score on a console chock full of noteworthy soundtracks.  It certainly fits the game like a glove.

Yeah, it's a pretty good one.  When the OST finally came out last year (I think), it didn't quite live up to my nostalgia of playing the game, but still well worth a listen.

This is one of my all-time favorite SNES soundtracks!
I love it way more than most Castlevania stuff.