I sympathize, bLind. I have no experience with 16-bit hacking, but when I was first trying to figure out how to crack open an 8-bit ROM, it was very frustrating and bewildering at first. Getting pointed to a bunch of random tools isn't necessarily helpful, especially if (like me) you're not a Windows user.
Besides, some of us learn best by taking an action that has a concrete, visible effect, and then reasoning backwards to figure out how it worked and what else we might do. Otherwise it can feel like you're in a sea of futility and nothing is making any sense. And to Google something, you need to have some idea of what you're looking for in the first place, and sometimes that's not clear! One person who's willing to offer specific, concrete help (instead of rolling their eyes or speaking in generalities) can save you hours of needless, misdirected effort.
Anyway, I'm interested in this game since I recently bought an original copy of it, so I tried nosing around in the ROM with TileMolester (4bpp linear, 2-dimensional mode) but wasn't able to make sense of what I found. I also played for a bit, went into the game's side-scrolling mode, and went into a building where a fellow had something to say to me in (mostly) hiragana:
The text display routine comes up one character at a time, so it's not just an image. I transcribed this as:
I then tried using a relative search program (OpenSearch) to find the text, but no luck. Perhaps I'm not using my program correctly -- I can't make sense of its wildcard function, so when I tried to use a search pattern that would allow for 2-byte encoding, it threw up nonsensical results. Or perhaps the text, too, is compressed.
If someone with better skills than mine can identify where the above text is located, then you'll be doing bLind a big kindness. Believe me, I know the feeling he's having!