In 1998, Nintendo announced that they were producing a new add-on
console called the Nintendo 64DD, a system that would sit
underneath the original N64 console and use larger, cheaper
disks. They would release a version of Ocarina of Time called
Ura Ocarina of Time that was rumoured to enlarge Hyrule, add
characters, dungeons and items that were not available in the
original game.
The N64DD was released in Japan in 1999 with a limited launch to
appease fans who had been rabidly awaiting its arrival. However,
with only 20,000 units produced, Nintendo's support soon
wavered. With such a small market, they gave away all N64DD
games, expansion paks and peripherals free with a subscription
to the Randnet service, an early foray into the online world.
After 5 months, games were no longer released, and Nintendo
cancelled Ura Ocarina of Time.
In 2002, it was announced that 100,000 lucky Japanese gamers
would receive a bonus disk when they pre-ordered The Wind Waker.
In it, they would find an emulated version of Ocarina of Time in
60fps and progressive-scan, but also, Ura Ocarina of Time. When
the disk came to America and Europe, the game was renamed
Ocarina of Time: Master Quest.
Gamer's soon found out that this wasn't so much an expansion of
Ocarina of Time as it was a remix. It followed a formula seen in
the original Legend of Zelda game where a second quest would
have the same overworld, while dungeons were made harder both
with trickier puzzles that played on your knowledge of the
previous quests, and also tougher enemies making earlier
appearances.