Credits Music: Cave Story (https://www.youtube.com/watch?v=wnH06vr13Wg) makes a second appearance in my picks, mostly because of all the credits music I can think of, it's one that I find to be particularly memorable.
Music I like from game I don't like: Castlevania 3's Japanese release (https://www.youtube.com/watch?v=ptgaCJSF7j8) has an amazing soundtrack (full playlist here) (https://www.youtube.com/playlist?list=PLgntNm0yymDxqON20-77GNHrIa0pS3Phq). While the international release's soundtrack isn't
bad, it does suffer from not having access to the amazing VRC6 expansion chip, which is easily my favorite of the Famicom's expansion chips. The music is great and it uses the VRC6 very well.
Its extra duty cycle options on its two pulse channels and its sawtooth channel make it an excellent compromise between being able to produce a variety of sounds and having lots of channels. It's outright better than the MMC5, as both provide 2 pulse channels, but the VRC6's are capable of making 4 additional unique duty cycles, and the VRC6 has a sawtooth channel that the MMC5 doesn't. The MMC5 can technically make one duty cycle (75%) that the VRC6 can't, but thanks to symmetry it sounds identical to the 25% duty cycle, which both chips can produce. The N163 and FDS can do arbitrary waveforms, which the VRC6 can't, but the FDS only provides one additional channel, while the N163's quality drops noticeably the more channels are added up to a maximum of 8. The VRC7 starts venturing into FM synthesis, so it's not really the same style anymore, and the sawtooth channel and duty cycle options are a considerable advantage over the ability to have additional noise channels you get from the Sunsoft 5B.
The game itself, however... ugh. I like Symphony of the Night and the similar Castlevania games that followed, but of the Castlevania games I've played that were released
prior to Symphony of the Night, I've hated all of them. The controls are a strong contender for the absolute stiffest I've ever seen (they're definitely the stiffest I've ever seen in a game that isn't generally considered bad), and the level design loves to present situations that would already be hard if the controls were fluid (why are there always medusa heads in the difficult platforming sections in all the classic Castlevanias?!) I find it kind of impressive that the series managed to last long enough for Symphony of the Night to be possible, considering how the earlier games are, but I guess things were different in the NES days, and these sorts of things were just more acceptable then than they are now.
I didn't select this particular song (https://www.youtube.com/watch?v=hzLxo5ggE6I) since I never made it that far in the game, but I've linked it anyway for a couple reasons: first, it's re-used in a later game (https://www.youtube.com/watch?v=JPDfc74foXk) that I actually think is good, and until I started sifting through the full OST I didn't know it debuted in this game. Second, it's probably the single track in the OST that benefits the most from the VRC6 - here's the regular NES version (https://www.youtube.com/watch?v=-Zmb2KGJcow).
Final Boss Music: Two picks for this one: First: Chrono Trigger: [Phase 1] (https://www.youtube.com/watch?v=-X1-uqDYa7w) [Phase 2] (https://www.youtube.com/watch?v=-QgUjqMxeXo) [Phase 3] (https://www.youtube.com/watch?v=IevXx3yQ77s) Phase 1 uses Lavos's main theme, so it perhaps isn't quite what you'd expect for boss music, but it's still a great song and it fits the atmosphere quite well, I think. But I really like how Phase 2 incorporates elements from Lavos's main theme into something that sounds a lot more like a boss theme.
Second: This one's much, much shorter, but it's a memorable boss fight with memorable music, and it's the first cinematic boss fight I remember coming across: Super Metroid's Mother Brain fight. (https://www.youtube.com/watch?v=Bwt740KznHE) The song's not quite as epic as Chrono Trigger's final boss music, but I've got a bit more nostalgia for this one.