The Adventure of Link. This is one of the wierdest Zelda games. Back when it came out in stores in the late eighties, it was an instant hit, but didn't rate especially high among gamers. This is because of all the differences between it and the first Zelda game. It was more of an RPG than the first one, and it was a sidescroller, like Mario. The enemies were meaner and harder. The bosses were bigger and stronger. The storyline was so much different, and so was the gameplay.
So many people loved the game, but there are also many who didn't. I, personally, think it is probably one of the better Zelda games. It is by far the hardest and most challenging, plus, a wider range of interactivity gives it something that Zelda 1 just didn't have. It is definitely a must have for any Zelda fan.