As explained on a previous development post (https://mastropiero.itch.io/spellbound-msx/devlog/513132/reworking-the-music), Spellbound had an excellent original music for the Commodore 64 that was totally spoiled when someone else (the name of the perpetrator remains undisclosed) converted it to the Amstrad CPC and later to the ZX Spectrum.

That was the version that I originally took for the MSX port of Spellbound but I decided to rewrite it entirely. There was too many musical mistakes (wrong notes, wrong chords, wrong scales, wrong tempo, wrong...everything). The PSG chip (AY-3-8910) is not as capable as the Commodore 64's SID is, so I haven't made a direct port from the original Commodore version. In fact, I have used the original ZX playback routines (that are very limited even for a AY-3-8910 chip). 

So, don't expect extremely complex chiptune tricks. Just some trills and a bit of ADSR modulation. Let's say that the main changes have been made to the music score.

Listen  to the resulting  score:

Since I have used the same routines and music format, I haven't got the original tools they used to encode the music composition. This means that I've encoded the new score directly in Z80 assembly! Do you think it is hard? No way. By defining the correct labels and macros it turned to be something close to regular MML language:

I have learned a lot during the process. This knowledge might be useful in the future if I decide to write a new BGM routine from scratch. 

Maybe for a new game?