I've had this idea for a long time now, but I'm not sure if it's possible:
Castlevania III (NES) with the improvements of the Japanese version. I know there is an excellent Japanese to English translation of Akumajou Densetsu, but that has its problems. One, you can't use English passwords, or any passwords to my knowledge(like HELP ME for 9 lives, or any passwords that allow you to start with a partner); and two, many sprites that were fixed in Castlevania III are back to their original, messed up, Japanese selves (Not talking about uncensoring, talking about stuff like the lesser demon, or the fact that Trevor uses his right hand to shake his partners' left hands, the mummies' coffins not being open when they come out, etc.).
What I was thinking was just to have a "Castlevania III with Famicom Music" hack. We already have an uncensoring hack, so a music hack would be the best thing for people who prefer the Famicom style.
I already know how to edit stuff like text, but music conversion is beyond me.