I've played the game, I have to say del, I'm somewhat dissapointed. First off, the bug ridden game can be fixed over time, but after listening throughall the tracks of music, brings me to some concern:
Most of theTracks aren't what i'd consider to be feudal era tracks, the only one i can spot that closely "fit" is the Civilization under the sun track.
When composing music, It's important to have an idea of how the music fits in with the setting, like D-Squall said Music is very important to esablish a gaming atmosphere. You aren't just making a game, you are making an interactive story, one that you share with the audience through your work. It's important that you make the atmosphere seem like the audience is getting sucked into the game, the music i've heard breaks that illusion.
The battle system is also important, if you are bringing in a certain element from RM2k into RMVX, bring back some of the many custom battle animations they have made that wowed and inspired. If you want advice on battle animations, I'm always here in the forums. And add atleast a themed background in the battle , the current one seems awkward at somecases.
But your game is not without merit. You have done your reasearch in the Japanese Department, for those who don't know, an onmyojo is a spirit warder, like an exorcist, so its not uncommon for her to have powers. And the chipset does give it the feel of a feudal era.
So for a future update, I suggest researching other videogames with japanese themes (Okami and The Demon Blade Muramasa) that will hopefully inspire you to compose music that adds the extra mile into forging this wonderful world that you have created. I hope this has given you an insight on how your game is. I'm one who plays for the true worth of the game, a game that can tell a story where you feel you are taking part and makes you this character in this story. It doesn't matter if you have fancy graphics or not, although it is highly recommended to have themed graphics, what's important is that you audience feels the environment in which you tell your story. Your halfway there, now dare to act.