The main concept behind Majora's Mask is the three-day cycle--every event in the game takes place over the course of the same three days. Each hour roughly translates to about a minute of game time, so the cycle must be restarted every hour. However, very early in the game, Link finds a way to work around this time limit with his ocarina: Link can slow down the flow of time by about three times, he can skip forward to dawn or dusk of the current day, and he can warp to owl statues littered across Termina to appear instantaneously in another area. Using these techniques, the time limit becomes much less restrictive with a little bit of planning. Tackling a Zelda dungeon in under three hours isn't all that difficult, and you can get a surprising amount of overworld quests done in the same amount of time.
The three-day cycle is done to great effect and places a heavy importance on everything the player does in Termina. The clock is constantly at the bottom of the screen, ticking down to the end of the world. As time passes and destruction nears, the game's music begins to get faster and more frantic, played in a darker and more sinister key. On the Final Day, the earth trembles at random and the sky turns an eery shade of green. In the final moments, the game clock becomes a flip clock, counting down the seconds until the moon crashes. While all of this lends an oppressive atmosphere to the game as a constant reminder of what's at stake, it can make the game feel pretty stressful. It's like an hour-long version of the Sonic the Hedgehogdrowning music or the manic "time's running out" theme from Super Mario Bros. Add to that the fact that the save system requires players to either record their progress at an owl statue without the ability to reload or to do a traditional save by restarting the three days, and there's a lot of pressure to make the most of one's time. This is probably the reason many people gave up on the game before reaching the first dungeon--they didn't realize that they were about to receive methods to alter the flow of time that would ease back on the intensity of the game. Still, the tone might be bleaker than what some are looking for in a Zelda adventure, so it's reasonable that so many Ocarina fans were disappointed in Majora's Mask.
Another major gameplay conceit in Majora's Mask is, appropriately enough, masks. Unlike the mask-trading side quest in Ocarina, Termina's masks often provide Link with a unique ability, like the Mask of Scents which allows Link to "see" smells--a skill he'd later have in wolf form for Twilight Princess--or the Blast Mask which allows Link to explode once every 20 seconds, at the expense of some of his health. The most important masks, though, are the three main transformation masks that allow Link to transform into a Deku Scrub, a Goron, or a Zora--each with their own animations, instruments, sound bites, and attack styles. The Deku Scrub can hop across the surface of a body of water and shoot bubbles out of its mouth like a slingshot, Goron Link can roll up into a ball to travel at high speeds and is immune to lava, and Zora Link can move freely in the water and shoot his fins out like two boomerangs. Each transformation also triggers different responses from NPCs--most people will treat the Deku like a child, are intimidated by the Goron, and are in awe of the Zora, while each respective race is more responsive to one of their own. It's really impressive how deep the characters can be just by following them through their days, but even more impressive once you realize that you can get multiple responses from some of them based on your appearance.
Exploration still plays a key role in the game, but it involves exploring the lives of characters rather than examining the nuances of the environment. Link goes through the same three days over and over again and gets to know the events in the lives of the townspeople intricately, much like the Bill Murray comedy, Groundhog Day. It's really fun following a character around for three days and seeing how their lives have been thrown into disarray by the Skull Kid, how they relate to their neighbors, and how they react to the knowledge that their world could very well end in the next few days. Some face their fates bravely, some resort to desperate measures, others just want one last moment of happiness before they accept their own death, and Link, the only one able to rewrite history, is their only hope. It's an oddly satisfying feeling walking through Termina late in the game and watching the NPCs go about their lives around you, knowing what the future holds for them. "Oh, there goes the circus leader. In a minute he'll find out that his show has been cancelled which will depress him enough to patronize the town's milk bar, annoying the bar's owner who is worried that they haven't been getting their shipments lately, before arguing with a band manager whose lead singer is missing her voice." It gives the player a strange sense of omniscience, and it's fulfilling knowing how to fix all of their problems.
It's fulfilling, that is, until you reset the three-day cycle and all the good you've done for these people is forgotten and erased. It's rewarding to help a person solve their dilemmas and receive a reward, but since some character plot-lines are intertwined, results don't carry over when the three days begin again. If one person's problem is already solved, then he or she wouldn't go through their three days in the same manner, and thus wouldn't be in the right location or the right mood to kick-start a portion of someone else's story. Even though, according to the plot, the changes you make do wind up ultimately occurring, over the course of the game the player is only allowed to enjoy the fruits of their labor until they play the Song of Time and reset events. This is also a problem when completing dungeons. Freeing each area's guardian giant from the Skull Kid's evil masks fixes the problems with that area. Termina's Southern Swamp, for example, has been poisoned and the Deku princess kidnapped. Upon completing the dungeon, the princess is returned and the swamp waters are cleansed and open up new pathways and ease travel in that area--but again, your success is only temporary, and to re-experience this reward, a player would have to re-enter the dungeon and defeat the boss again, although, the puzzles and doors would remain solved; there is the option to face the boss upon immediately entering a completed dungeon.
Side quests also tend to emphasize character interaction. In this sense, the game has a lot in common with adventure games. Many of the side quests involve finding the right item and giving it to the right person at the right time after following them and seeing what they need to complete their goals before the moon drops. Many of the people need help multiple times over the course of three days and their lives affect other townsfolk, the most notable of which involves helping an engaged couple reunite before the world ends. Some of the NPC-quests are more traditionally skill-based, but even these put you in pretty unique situations for the series; at different points in the game, Link is tasked with performing as the house band of a milk bar, preventing cattle from being abducted by aliens, and stopping the mugging of an old woman late at night. You'll still solve environmental puzzles, traverse dungeons, and battle bosses, but Majora's Mask puts decidedly more emphasis on the adventure aspects of the action-adventure genre. Whereas most Zelda games are about 10%-20% plot and character focused, Majora's Mask is probably an even split: 50/50.
The traditional Zelda gameplay is still in there, though. The game has four main dungeons, a number of mini-dungeons, and some of the more creative and difficult bosses the series has had in a long time. One boss is a giant mechanical goat that runs around a ring shaped arena, and Link has to chase him down in ball form as a Goron and take out his legs to attack him. Another boss has Link growing to giant size to take them down amid (relatively) tiny pyramids and obelisks. A few of the dungeons require some deep thought when trying to get from place-to-place, much like the City in the Sky from Twilight Princess or the infamous Water Temple from Ocarina of Time. The fourth dungeon, however, is the Stone Tower, and is irritating for many of the same reasons that the aforementioned Water Temple is. Many of the puzzles in that section of the game require Link to play a long song on his ocarina and switch transformationmasks multiple times to make any progress. Going in and out of the menu just adds to the tedium of that temple, which is otherwise pretty interesting for its gravity-flipping puzzle mechanics.
While the three-day cycle allowed Nintendo to try new gameplay ideas and plot concepts, it wasn't perfect. As one could probably assume, forcing Link to repeat the same three days constantly can get a bit... repetitive. There are many instances in the game where the player will know exactly what they have to do, but they're stuck waiting for the right person to show up or for the right shop to open. Even if the longest wait is five minutes for a location to open or a cutscene to trigger, that's still five minutes where the player is not involved in the game and it really kills the pacing of the adventure. Gamers will also come across instances where they'll show up seconds late to deliver an item or escort a character, and must start the entire quest over again from the beginning. Most of the clues towards what a character needs or what abilities are required to complete a quest are really subtle, or require objects that may not have been obtained yet, which makes the time spent on them a wasted opportunity to advance in the game. The emphasis on these side storylines serve to draw the game out, though, and most people will probably lose their drive by the time they hit the last of the four dungeons. The endgame is ultimately worth it, and really satisfying, but the game is just a bit too slow in leading up to it.
There are plenty of rewards for gamers that seek to complete everything that the game has to offer, which is refreshing compared to other games in the series. Majora's Mask is one of the best Zelda games in terms of "bonus items" that are not required to complete the game. In addition to the usual hearts and the abundant masks, thorough players can also gain access to three different upgraded swords, up to six bottles, more health and magic, stronger offensive and defensive abilities, and most importantly, the Fierce Deity Mask which is rewarded for collecting every other mask in the game. The Fierce Deity Mask is usable only during boss battles and transforms Link into a white-garbed god, three-times his normal size, with a large and powerful sword that shoots energy projectiles at long distances--a throwback to the projectile swords and the white tunic from the 2D Zelda games. It's the ultimate form of fan service that allows Link to take down the game's difficult bosses in a matter of seconds.
Technically, the game is dated, but holds up fairly well. It improves on Ocarina pretty successfully in some key areas: the image is crisper, the color is brighter, and there's more on-screen at any given time when compared to its predecessor. Despite the increased RAM from the Expansion Pak, though, the game still suffers from slow-down during some of the more complicated boss fights, which is disappointing. The graphics are still blocky and dated, but the animations are pretty impressive, considering when the game was released, and they really sell some of the jokes, personalities, and plot-points in the game. The lack of direct camera control is still a significant problem that lock-on targeting only partially solves. Epona's controls have been refined somewhat, and she's less finicky, although she still steers a bit like a tank. The ability to skip and speed up text is very welcome, but practically a necessity, since you'll be getting repeat dialog every time you restart the three-day cycle. Majora reuses and remixes some of the more famous themes from Ocarina, but manages to add some classic songs of its own. Also of note is the return of the main Zelda theme song to the overworld, which was oddly and notably absent from Ocarina of Time.
The annoying Navi character has been replaced with Tatl, who offers her advice much less often and does so with a jingling bell noise, rather than the ever-infuriating, "Hey! Listen!" She has more of a personality when she does talk, too, being more sarcastic and dismissive then the usually milquetoast Navi and providing a surrogate "voice" for Link in important scenes. Kaepora Gaebora shows up in the game only twice, and is much less long-winded than he was in Ocarina of Time. It seems like Nintendo was listening to these complaints when they began work on this follow-up. One of the main additions to the Zelda cast in Majora, however, is the mostly reviled Tingle--a 35-year-old man who dresses in a green spandex body suit, dreams of having a fairy, and floats through the air with a backpack-concealed balloon. While the character is still as disturbingly odd and irritating in Majora's Mask as he'd later become known for, his character at least makes sense in this game, as he's a resident of Termina, Hyrule's own twisted version of Wonderland where plants will scatter in fear if you cut one of their number down. You only interact with Tingle a handful of times to buy maps for each of the games overworld locations, and aside from that, he's relatively unobtrusive. At the time, fan reactions in the United States were unkind, which makes it even odder that Nintendo utilized him so often in the series going forward. Hell, he even eventually got his own game in certain regions! He's easily ignored though, and has little effect on the quality of Majora's Mask.
In the end, due to the oppressive tone, the amount of time spent with the characters, and the complex plot, Majora's Mask tends to have one of the more unique and interesting stories in the Zelda series. While it's technically similar to Ocarina of Time, the game is functionally very different, with its slower and more deliberate pace and its emphasis on relationships and plot over action and dungeons. It takes familiar items, characters, and themes from Ocarina and inverts them, allowing for a game that's simultaneously familiar and radical for the series.