"I never played Skyward Sword but I read an article that claims that game had a similar "hard mode" that could be toggled on or off. For those of you that have played Skyward Sword, does it have a harder difficulty setting, did you ever play with it on, and what did you think of it?" - Michael117
It goes by the same name in Skyward Sword. You can't toggle it on or off.
I played it for about an hour after a finished the game, and I can say that it definitely got more challenging. You need to focus your attention on pattern striking a lot more because you can't go loosing hearts all willi nilly, and as a basis for comparison the "normal mode" of the game was harder than most recent 3D LoZ games. I wouldn't know how it faired in dungeons/bosses as I didn't go that far, but I can totally see it being a bitch to play.