I suck and I could never get past dungeon 3, but the text I found in the ROM suggested there was a plot line throughout the game intended at some point. Definitely worth checking out. (I posted a font table in that message board thread, and it is in the neighborhood of offset 50000 in the ROM (script contains both Japanese and English translations of each line, though who decided "Tairyoku wo kaifukushita" ("Vitality recovered".) translated to "DELICIOUS"?

). At least according to the post I made. And it's actually the US ROM that seems to have added 256KB to the ROM for no reason.