I like the exploration and story behind the games, since I prefer story-driven games rather than good graphics or whatever kids these days care about. Plus, I like how they made a formula for the series that they aren't afraid to break (Majora's Mask is a perfect example of this). I also like how they all have similar ideas behind the story, yet they are each their own. Ocarina of Time was the one that involved traveling through time, Twilight Princess was a bit dark and travelled through space, and Skyward Sword has Link and Zelda as childhood friends, and has Link traveling between two worlds. Link to the Past and Link Between Worlds involved traveling between light and dark worlds, which were parallel universes. And then there's the oddball Majora's Mask that puts Link in an alternate dimension where the moon is going to destroy the world in three days, and Zelda has pretty much no role in the story (other than the flashback where Link remembers the Song of Time). The Legend of Zelda series is an amazing series and each game is memorable in its own way.