After just a few days, I have beaten Super Ninja Boy. It's one I've beaten before, but again falls into the camp of "I've not beaten it since picking up this physical copy" - if I'm gonna buy a game, I wanna beat it - nothing is just shelf candy, save perhaps for a very few sealed or otherwise special items.
I have fond memories of this game and playing through again years later has mostly not soured those memories. It has more than its fair share of backtracking and the encounter rate can be quite high at times, but overall I still like the game a lot. I went out of my way to pick up the strongest armor, but I didn't bother to grind out the Hypnoblow which you have to either get really lucky and win it in a game of chance, or grind out 200,000 SEN (the game's main currency) to purchase it. When I beat the game I had around 70,000 SEN, so... yeah, I wasn't about to grind out the way overpowered punch just to make an already really easy end boss even easier (though one-shotting him might have been funny).
The translation could definitely use some work, paired with the story being pretty weak-sauce. If you are an RPG person the battles which are mini beat em ups also may not appeal. I personally had some pretty good times as a kid playing with my brother (two player RPG!) and it was fun to mix it up by punching each other every so often. As a single player endeavor the turn-based boss battles can be a bit weary as your uncontrolled partner will pretty well always use the shittiest possible attacks, but it's easy enough to compensate especially around the middle of the game and beyond when you start to get overpowered compared to the bosses.
Decent game I have a lot of nostalgia for, and now I can consider my boxed copy well earned.