The Legend of Zelda: Ocarina of Time Master Quest
Master Quest is a notably difficult version of The Legend of Zelda: Ocarina of Time. It was originally released on the GameCube with the original Ocarina of Time. It could also be unlocked in Ocarina of Time 3D.
Dungeons are completely redesigned in this version of the game, and certain items that were previously optional are now mandatory. Items and Pieces of Hearts inside of dungeons have switched places, and new puzzles are created. However, the story, locations, and characters remain completely unchanged from the original. Sidequests and locations of items outside of dungeons are also the same.
Master Quest is also found in Ocarina of Time 3D. Though it is not available from the start of the game, the player can unlock it by completing the original version. The redesigned dungeons are the same as the ones in the GameCube version. However, this version also flipped the entire game. Everything in the 3D version of Master Quest is mirrored. In addition, enemies now do twice the damage.