Sequels on the NES usually went either way. Either they were completely different to the originals, or they were identical, just with a new feature or two.
Zelda II was released by Nintendo in 1988. It was a firm departure from the overhead dungeon crawler of the first Legend of Zelda.
Zelda II took the approach of an RPG this time round. Link travelled around the map, leveling up, collecting items and gaining spells. It's still debated between fans on the true nature of this game. However, it's still considered to be one of the greatest Zelda games ever made.