I don't really recommend this game if you're starting out/getting interested into the Metroid series. Metroid on the NES isn't a very good game due to the fact that the controls are very clunky and the game has slowdowns on NES hardware. You don't have complete diagonal aiming, so enemies are sometimes difficult to hit, plus I had a much easier time cheating at the game by shooting with turbo rather than genuinely playing with patience.

I don't know if there's any difference playing this version vs. the famicom version, but I really don't care to find out considering how awful of a time I've had with this one.

I've played a little bit of Zero Mission but never formally finished it, so I can easily recommend starting with that if you're interested within the series, or even starting with Super Metroid.