Majora's Mask n64 for a lot of reasons:
- Best 3d Dungeons: I love how the dungeon layouts can be manipulated, and even though there are less dungeons, they are some of the best in the series
- Best 3d Bosses: Goht is my favorite Zelda boss ever, and honestly, all the boss battles in this game are fun and creative
- Great Side Content: I love side quests in games in general since I love interacting with the world and Majora's Mask has great ones. They each have their own unique little story or some fun gameplay. Theres also other fun side content like the Spider Houses and the Deku Race
- 3 Day Time Mechanic: its very detailed, and since you can always reset it, it makes the time element fun for certain side quests, unstressful when exploring, but stressful during dungeons and trying to get those stray fairies to the great fairy. Best done timer in any video game
- The Masks: especially the transformation masks, I love the different abilities the masks can give you, which definitely made up a lot for that with the masks
- The World: Termina is my personal favorite Zelda world from any Zelda game. Its wierdness makes everything interesting and unique and its the kind of world that even though its small its fun to explore it and find everything in it
- Moon feels like a Threat: Ganon rarely feels like a threat in most Zelda games, but the moon always feels like a great threat and the third day does a good job of making you feel that
- The Music: some of Zelda's best tracks, Song of Healing is one of my favorite Zelda songs of all time, and some of my favorites from OOT were brought back, like Song of Storms. Also Final Hours is an incredible soundtrack since it makes the third day feel like the world is about to end
- The Atmosphere: I like the dark creepy atmosphere of this game
- Great Characters: I love the characters in this game. Every single character has their own unique story and side quest, and I love seeing all the characters react to the moon falling. They are a lot better and more developed then Ocarina of Time's characters IMO