Here's the games sound track in MP3 format. When Castlevania II was first released over here, the sound test screen just had generic "BGM 1" and so on in the sound test menu, but when it was re-released in Konami GB Collection 4, they bothered to translate the names of the music tracks. There are no typos below by the way, this what they are spelt like in the sound test menu.

Track name
Used in:
All Clear
Dracula's defeat
Password screen
Castle 2
Dracula's castle map screen
Castle Selected
Castle chosen at select screen
C. Phantasie
Battle against Soleiyu
Christopher died
End of the Day
Credits sequence
Evil Gods
Boss theme
Soleiyu cut-scenes
Game Over
Game Over screen
Journey of Chaos
Castle select screen
Original Sin
Dracula's castle part 1
Intro sequence
New Messiah
Crystal Castle
Dracula's castle part 2
Praying Hands
Cloud Castle
Psycho Warrior
Rock Castle
Ripe Seeds
Plant Castle
Road to the Enemy
Pre-boss battle
Road to the Enemy 2
Final stage
Soleiyu's Room
Pre-Soleiyu battle
Sons of Satan
Battle against Dracula
Stage Clear
Boss beaten (excluding Dracula)
Ending sequence
Welcome to Hell
Title screen