The story of this one is, in a way, the reverse of every other game in the series. In every other game, you are going through various temples and dungeons in order to collect items which will give you the power to defeat which ever enemy you are up against, while in this game you go through the temples in order to return crystals to them. You need to do this in order to stop Ganon's minions, who're trying to kill you in order to use your blood to revive him, and also in order to wake up a Zelda who has been in some kind of coma for centuries.
Now, as I said in the opening paragraph, this game is both 2D and very difficult. However, it isn't entirely a side scroller, you still walk around on a huge world map (like the first game) accept whenever you encounter an enemy, a town, cave, or dungeon, you'll be put onto a new 2D map. I think the 2D side of things is partly what adds to the difficulty, sword fighting suddenly becomes a lot harder and skill based than it was in the previous game (and would later be in others) and, aside from a few limited magic spells, this is all you can do to attack enemies. You can stab upward or downward, and the enemies can do the same, and you each also have a shield to block, it's very fast paced and very hard. This game is so hard, in fact, that were it not for save states on the 3DS, I would never have been able to finish it!
The game's towns are one of the high points, unlike the barren Hyrule of the first game, there are now loads of populated towns full of people to talk to. A lot of the people will just say irrelevant things, such as "Hello, young man", but some of them will give you cryptic clues about what to do next and/or secrets hidden in the game which will encourage you to explore more and more. I certainly found myself wanting to explore and check every little corner of the game in order to find everything.
So, on the whole, while its difficulty is a huge set-back, this is still a very enjoyable Zelda game and certainly not the worst one! I'd highly recommend buying the 3DS version over any other though, simply due to the save states! I'd rate it 8.4/10
(I do not own the copyright of the title screen.)