Back when Nintendo were developing The Legend of Zelda: Ocarina of Time on the Nintendo 64, they were doing so within the tight constraints of its limited memory capacity. No one was quite sure just how vast a game the hardware would be capable of supporting, but Nintendo’s developers were relying on previous experience with Super Mario 64 and Star Fox 64 to help guide them along.
Preferring to start out more conservatively in light of this issue, when development began, Zelda creator Shigeru Miyamoto’s initial plan was to have the entire game set inside Ganon’s castle, similar to Super Mario 64, to help conserve memory.
“I thought about putting in all kinds of adventures into the different rooms, like making a dark meadow or an ocean — like in Princess Peach’s Castle in Super Mario 64,” Miyamoto told Nintendo president, Satoru Iwata, in the final Iwata Asks feature on Ocarina of Time 3D. Miyamoto wasn’t sure the N64 would be capable of supporting a large landscape like Ocarina’s Hyrule Field.
Miyamoto says that by extension, the game may have turned out like a 3D version of Zelda II: The Adventure of Link. As long as they were able to create Link in 3D and realize the scope of the story, Miyamoto didn’t mind limiting the actual areas to different rooms in Ganon’s castle.
In fact, prior to this, Nintendo had experimented with creating a polygonal version of Zelda II: The Adventure of Link for the Super Famicom system, partly as an experiment to realize a sword-fighting system that was ultimately fleshed out in Ocarina. This game, however, never ended up seeing the light of day.
The boss fight with Phantom Ganon at the end of the Forest Temple, Miyamoto revealed, was a concept left over from the idea of basing Ocarina of Time entirely inside Ganon’s castle. Ultimately, the concept of Hyrule Field and the ability to ride a horse resulted in the game’s development taking a more ambitious turn.