It is the 'worst' selling console Zelda game, if you exclude Four Swords Adventures.
The game suffers from the 'second game syndrome', which affects all 2nd Zelda games on any particular console. All second Zelda games on a console (true for both console and handheld games) sell significantly worse than the first, but still it managed about 3.4m coupies which is not dramatic. The Adventure of Link actually was the best selling 'second' game and came relatively the closest to it's predecessor.
Anyway, Majora's Mask is pretty much only praised on the internet. It's basically because it's different from what is usually percieved as 'the regular Zelda game' (even though they're all different) and because it's massively overshadowed in both popularity and recognition by predecessor Ocarina of Time in the real world. Still, like all Zelda games, a great game, but definitely not the best. Personally, I'd rank it (in descending order): Ocarina of Time > Link's Awakening > Twilight Princess > Majora's Mask > Skyward Sword > the others.
Wouldn't this mean that Zelda U will sell less than the WW remake? ^^ But yeah, I've heard (and seen) that the second games on any console sell less for the Zelda series...
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