Great work! I was actually about to start playing the sequel as I could not stand the first one on msx, this pce version is way more bearable and I was finally able to play, enjoy and finish this game. Not the best game ever but an interesting one nonetheless. Anyway I found what I think its a game breaking bug right in the end of the game, without getting into detail, you need to open a door after you acquire 6 holy relics, what happens is that, somewhere around the line, you get an story related item (a picture) that you are not supposed to have in your inventory when you get there, if you happen to have that item, the last dialogue box before the door will glitch and the door will remain permanently closed. I fixed this going back to the church, getting a password, resetting the game and inputting the aforementioned code. I think this happen because I played all the game on "single seating" since I have been playing on retroarch and I used savesates instead of the password system.
I hope this can help if anybody finds him/herself on the same situation.