Hey, you got further along than me. There is only so much you can do by randomly talking to people. It might be a case of me putting up a short article explaining this game, and hoping someone who knows Japanese takes interest in it. If you look on Google, there is next to no information on this game. It kind of surprises me that there hasn't even been a translation group that even had a look at it.
I went ahead and did an article. I pointed out that this prototype is indeed not the same as the final version, but it is beyond my level of expertise to be able to delve into it. Click here
I put up another prototype. This time, Pikiinya!, a fun Tetris-style game. The prototype is fairly close to final, I reckon. Click here
Here is a sample of Ganbare Goemon 3. http://www.snescentral.com/review.php?id=1052&num=0&fancy=yes&article=proto Might be my last prototype article until November. Going to be busy, then on holiday.