Zelda II: The Adventure of Link is easily the most controversial game in the series (no, not counting the CD-I games). Whether you love or hate the side scrolling, action-based combat and steep difficulty, there is no denying this sequel has some of the best music in the entire series.
Personally, I think the opening to Zelda II might be my favorite Zelda tune of all time. Which is I looped the opening for 1 continuous hour! The tune makes for great background noise or theme music if you want to go on your most “adventuresome” quest yet.