I've learned my way to Act 7 of "Ninja Gaiden III: The Ancient Ship of Doom"... The length of the game being drawn out kind of reminds me of Metal Slug III. In MS3, the final stage is drawn out to being about 3/4 of the length of the game as a developer's joke. Act 5 in NG3, was long and intense enough to be the ending act, and then came Act 6, and now Act 7. I wouldn't be shocked if there's an eighth act by now. I like the game a lot, or I would have given up playing it quite early on, but I really can't play past Act 5 without taking an hour or two break... so to me, that says they stretched the game out far too long to not implement a save or password function.
I'm also fooling around in "Legendary Wings". I don't know if my hands can handle playing that game through, but it is rather fun. I got to the first level's end boss(I died) after quite a few fatiguing attempts, and came to the conclusion, that it was probably designed to sell turbo controllers like the MAX or Advantage. The best I have is the Dogbone controller, which I had to switch to because the old style one was digging into my hands when holding a good enough grip to rapidly tap the the fire button.