I played Ninja Taro for the original Gameboy a couple of years ago using a FAQ. Unfortunately, the FAQ was not quite finished so I ended up not knowing what to do next. It's not that the game is super arbitrary, however, since I was so dependent on the FAQ, I wasn't paying much attention to the clues and details given by the NPCs.
Now that that's out of the way, let me tell you about the game. Ninja Taro is a Zelda clone. A damn good one at that. Basically, you are a ninja and you need to do something or other for your master. Hah, it was so long ago that I forgot the stupid story of the game and I'm too lazy to look it up on Wikipedia. Anyway, you are a ninja, so you get a sword, ninja stars, and some other cool weapon upgrades. As with Zelda mechanic, you cannot access some of the places yet without getting the necessary equipment. For example, you need a sickle if you want to cross gaps or you need an ax in order to chop down some trees. That kind of thing.
This game is great! I have to say that I like this one better than even any Zelda for the Gameboy original or Gameboy Color. The medieval Japanese backdrop is appropriate and a breath of fresh air. The monsters are balls hard. The puzzles are all logical even without a FAQ. The game's graphics are not too shabby either. The art is cutesy and whimsical, but it is appropriate to the theme of the game and does not subtract from my enjoyment of the gameplay.
If you have a Gameboy emulator (a Dingoo a320) or if you own a real Gameboy, track this game down and play it.