The instruction manual is 48 pages of in-depth explanations, devoting 6 pages to backstory alone.
The manual describes how Ganon got his hands on the Triforce, corrupted the Golden Land, and became a beast.
After vanquishing his own followers, the leader stood triumphant before the Triforce and grasped it with his blood-stained hands. He heard a whispered voice: "If thou hast a strong desire or dream, wish for it..." And in reply, the roaring laughter of the brigand leader echoed across time and space and even reached the far-off land of Hyrule.
All is lost, the villain has flown off, there's no possible way to follow him... fade to black... ...cue ocarina, summoning the stone duck across the dimensional divide...
Agahnim is probably one of the most competent Zelda villains; he kills the King and apparently vaporizes the maidens, including Zelda—the latter right before Link's eyes. When he's defeated the first time, he transports Link to the Dark World.
The fight where you have lightning and magic spells thrown at you by Agahnim. It's so cool how you can deflect them with your butterfly net.
This is the first game in the series where Ganon has the entire Triforce. Link still wins.