A great story and a fairly stiff challenge across cool and foreboding levels makes this an amazing game, then and now.
Again, as Ryu Hayabusa, ninja superman, you rely on carefully timed jumps, your trusty sword, and various magic abilities that you'll find (and again you can only carry one at a time), to progress your way through increasingly difficult levels, which to this game's credit are more varied than the first Gaiden. You'll run your way across a train, traverse treacherous peaks with a blizzard that can push you to your death, go through a forest relying on only occasional lighting to be able to see the pits and enemies all around you clearly, and eventually end up in some pretty bizarre levels.
This game is not quite as brutally challenging as its predecessor either, perhaps due to there being more checkpoints with less nasty boss fights. Though don't think for a second that it's going to be easy either. There are MANY different types of enemies, and most of them can be a nuisance to deal with, especially when you have to handle 4 or 5 at a time while jumping over pits. Also, since there's a few more checkpoints and a bit more story, this game seems to flow more smoothly or briskly than part one, with less having to repeat a stage 24 times before progressing.
The game play itself is all about timing. Each enemy has a basic attack pattern, but there's so many different enemies that it's hard to just hack your way through all of them without taking damage along the way. At many times throughout your journey you will have frantic encounters and rely on literally split second timing to survive. That's the bread and butter of this game - dealing with a challenge that forces you to become an inhuman reflex machine and the sense of satisfaction that goes along with that. You'll be more than happy to beat this game all over again once you've finished it.
The last great thing to mention is the music - every single tune is great, from foreboding and evil music, to more high tempo catchy stuff that really suits the action perfectly. The sound effects are also gratifying - you'll learn to appreciate the generic exploding sound that your vanquished enemies make. Yet another classic title for the virtual console.