Hello Takuma,
I have played some of your game and I must say you should be proud of what you made. It is very authentic to nes rpgs to the point that it could almost be a lost one, but the 'crustyness' of those old games is polished off in this one. The guides/instruction book feel the same way have a high degree of production value. I can tell you had a lot of fun putting this together!
It was fun exploring a lost nes game, and think this game deserves more visibility. The only real suggestion I would make is to have an option for enemies to give more exp/gold for players who want to not have to grind for money/exp.