Originally released in Japan in 1991, The Legend of Zelda: A Link to the Past was released in North America and Europe in 1992 on the Super Nintendo Entertainment System (SNES). This game featured the series trademark hero, Link, on a quest to save the Princess of Hyrule, Zelda, who had been kidnapped by the evil wizard Agahnim. The game marked a return to the series' 2D overhead roots, which Zelda II: The Adventure of Link departed from. It is considered by many to be the best game in the series, though it is not quite as popular as Ocarina of Time.
The story of Link to the Past follows a young boy named Link who is contacted by a princess named Zelda. After rescuing her from a wizard named Agahnim, Link sets out upon a quest to retrieve the Master Sword and three mystical pendants. With the Master Sword eventually in-hand, Link defeats Agahnim, but is subsequently teleported into the Dark World version of Hyrule. Once there, Link sets off to find and defeat Agahnim yet again, but must first find the seven descendants of the Seven Sages throughout temples in the Dark World. After freeing the descendants throughout the Dark World, Link does battle with the Agahnim, and upon defeating him finds Ganon where Agahnim's remains lie. The final battle against Ganon ensues.
A major concept in Link to the Past is that a dark version of everything in Hyrule exists in a realm known as the "Dark World". This world was once a Sacred Realm until Ganon arrived and used the Triforce to bend the realm to his will, covering the land with darkness and despair. Throughout the course of the game, Link must travel between the Light World and the Dark World in order to complete certain puzzles and progress through the game's story. Some areas of the Light and Dark worlds are identical, but others have minute differences that alter Link's ability to travel through them. At first, Link is transformed into a reflection of his inner self whenever entering the Dark World, which leaves him unable to use items or wield a sword and shield, but eventually he collects an item that allows him to maintain his form while traveling through the Dark World (much to the surprise of the world's natural inhabitants).
About half of the game takes place in the Light World. Link must win three pendants in order to obtain the Master Sword, as well as defeat Agahnim at the top of Hyrule Castle. Most of the second half of the game takes place in the Dark World, where Link must revisit the seven temples which differ from their Light World counterparts significantly. While traversing the Dark World dungeons, it is sometimes necessary to travel to the Light World to manipulate an object, and then return to the Dark World where a consequence of that manipulation will allow Link to progress further. An example of this can be found when traversing the Dark World's water temple, as Link must first open two flood switches in the Light World's counterpart in order to allow him to venture further.
While this " parallel world" mechanic made its first appearance in Link to the Past, it certainly wasn't the last Zelda game to use it. Ocarina of Time and Twilight Princess both included the ability to travel between parallel worlds, and many believe that this mechanic played a significant role in the success of each of these Zelda games.
The structure of the game adheres to the formula of the series, of which this game is the prime example. Exploration of the towns and overworld is broken up by dungeon exploration, which involves solving puzzles and facing enemies, including a boss and a miniboss. In each dungeon, Link will find a new item that will allow him to solve puzzles or reach new areas, while also providing a key role in besting that dugeon's boss.
These shoes (renamed boots in the GBA version) allow Link to perform a dash. He will continue to run in a straight line until the player stops him or he crashes into an obstacle. The resulting crash can be used to break down certain walls or cause items to appear.
These flippers allow Link to swim. His purchase of these flippers also allows him to use whirlpools as warp points.
Possession of this mystical artifact allows the owner to keep his true form in the Dark World. If Link does not possess this item when entering the Dark World, he will become a pink bunny.