This Legend of Zelda aims to transcend the element of time not yet explored. Link is born into Hyrule in an indeterminate age. The land is dotted in millennia of ruins, built over layer by layer, melting into a miasma of architecture and artifact tied not to any given time—the origin of endless stories enough to scramble any concrete history these people once had. Lost to time, the remnant people of this age tell the many Legends of Zelda as mythological history.
Link aptly begins his journey in a village at the base of the land's highest mountain. The village would serve as the 'tutorial hub', sending Link off on his first quest to climb the mountain. Upon reaching the top, he finds himself immersed in the ruins of an ancient temple. Standing in the center is a door, brooding as it is inviting. As Link approaches, from behind it steps an old woman. She addresses herself as Alda, Voice of the Door. After explaining the precedent of the Door, she reveals from the sleeve of her robe three stones, which she refers to as Ageorbs. Link must choose one and with it, insert into a circular orifice lining the frame of the Door. Upon doing so, light cracks through the edges of the frame, pushing open the doors. A holomirage appears within the doorway, flashing rapidly imagery of the land this door now leads to. Alda explains to Link the journey he is about to embark on, and so he steps through the Door of Time.
Depending on which Ageorb you chose, Link has traveled to one of three lost ages of Hyrule. Each age serves as a "level", deploying Link into an explorable world (albeit not expansively as a full Hyrule experience would) with side-quests and a dungeon to conquer. Upon completing said dungeon, Link is awarded a new Ageorb. A holographic door emerges in the boss room which he can step through. Upon doing so, he walks back through the Door of Time and is greeted by Alda who inquires about his journey. With this new Ageorb, he places it in the next frame slot and activates passage to another lost age of Hyrule. Each age has a dungeon and side quests (sometimes optional dungeons) that require cross-age transcendence to acquire items necessary for progression. Each dungeon yields an Ageorb upon completion, expanding Link's potential story. Items are found within the age's world, then usefully applied in the dungeons. Some dungeons cannot be completed without certain items, and said items might not be found in the corresponding age, so transcendence through time is necessary. The acquisition of items through traveling the ages will yield further exploration into dungeons and thus, access to more ages.
There are a total of nine Ageorb slots lining the Door of Time, so while you may collect many more than nine Ageorbs, only nine may be loaded into the door. Upon returning for the first time from a lost age, you will notice characteristics of that time emerging within your world. You are essentially resurrecting elements of Hyrule's lost past to reshape the land into something it's never been. Ruins will restore, disappear, and transform into totally different structures. Regions will unlock depending on their age-intrinsic aspects. Your Ageorb choices actually matter. You are writing Hyrulean history.
Ultimately, upon filling all nine Ageorb slots and conquering your chosen ages, you will have crafted a completely explorable Hyrule contingent on your choices. Each age will load into the cohesive Hyrule varied aspects that must be programmed to work no matter the combination of Ageorbs. The tenth age is your age. It is the age of your writing. This Legend of Zelda gives the power to the player. Hyrule is truly in your hands. Your choices, your story, your world. After choosing and completing your nine lost ages, you will have unlimited access to explore the tenth age, the transformed age. The age that began as the zeroth, the age of ruin. The beginning of the game is the age of ruin. There is a calm, but there is emptiness. The Door of Time allows for Link, the Hero of Time, to restore Hyrule how he sees fit, without time spent in reconstructive passage.
*Spoilers!* After the completion of the 9th Age to fill the last void of Hyrule, Alda draws her hood and reveals with shining blue eyes to be Zelda, the last sage. Long after her reign as Princess of Hyrule, she retired to protect the Temple of Time as the Sage of Time. She saw Hyrule fall into ruin by ruin (Hyruin, heh). It was not until the Hero's spirit birthed again into the world that she felt hope for the first time in restoring it. A curse had been placed on time itself, cycling all history into convoluted ruin. No civilization was allowed to last—even Link's remnant village was nearing its death and with it, the last people of Hyrule. As the Sage of Time, Zelda (who in Ben Kenobi fashion, took the moniker Alda) held a grip on the last untainted aspect of time, the Door. Even its protective temple lay in ruin. Only the Door of Time, fueled by Zelda's life stood in place and function. Both she and the door shared life.
The antagonist of this game is time itself, or more specifically, the source of infinite ruin through time compression (hmm.. Final Fantasy VIII..). Upon reaching the tenth age, Hyrule is restored, but only in a reprieve of time. The threat is not stopped. At this point in the game, you have all the time in the world to meander around, exploring to your heart's content. Huge satisfaction. However, in order to complete the game, the last (tenth) dungeon must be conquered, which is accessed from your newly crafted Hyrule. Access to the dungeon will once again be via the Door of Time, though empowered with all nine Ageorbs. Inverse of the single-orb access into the nine lost ages, all nine will cohesively create passage to the antagonist's realm, which too will reflect your choices. Such power not even Ganon could fathom.
This is a world of nethertime. Nothing is concrete in its placement. Foes will warp in an out of battle if not defeated swiftly, to be replaced with other types as if every possible timeline within this world shifts rapidly. Objects will disappear and transform rapidly, ever-changing the environment around you—all of which is generated in response to the Ageorbs you chose to activate this world with. Did one of your Ageorbs lead you to a fiery holocaustic Hyrule with the destruction of Death Mountain immolating the skies and green of the world? Expect fire to cast a brooding effect on the world, if only in the blink of an eye. Did one of the Ageorbs cast you into a Zora-ruled Hyrule, with artificial sluices constructed and carved into the archi-geography of the land for quick transportation? Expect such derivative elements to be found here, only turned against you. Everything you got to enjoy about your constructed tenth age Hyrule is now against you, and in constant transformation. The illusion of time and space is being bent even further to crush you as your perception does not belong in this world. You are a virus to its paradigm. It does not want you.
This world is the antagonist and destruction of its heart is the key to saving Hyrule from its inevitable corrosion... Upon doing so, you return through the door for the very last time. The doors close and the Ageorbs dim, exhausting their light. The energy fueling the door has finally come to an end. The tear in time has been healed and all that was chosen to converge breathes new life into the fabled land of Hyrule, all under your command. Every era of Hyrule's history has converged into the Tenth Age; the branched timeline ends, and with the last breath of the door, Zelda dies. This is The Legend of Zelda.
