Hmm. I played the original Gameboy version of Seiken Densetsu (Mystic Quest here in Europe) and Secret of Mana to the excess, completed both multiple times. Secret of Mana 2 not so much. Will consider this but not in Japanese. Let's see if we get at least an English version, although Mystic Quest and Secret of Mana were both available in German. Not sure bout the Seiken Densetsu remake that came out like one or two years ago, for Android (iPhone?) and Vita.
Edit, nvm, didn't watch the video - it's indeed the original Gameboy release which I find rather odd considering there is a 1:1 modern gfx remake already out. That seems a strange decision. I can just inject the roms into 3ds VC myself and have exactly the same outcome, and even the first two games in German.
I honestly don't like where this is going. Just release it as VC for like (still too much) 8€ per game, like they do on 3ds, but not fill price on cart for simple emulations.