Forerunner City

"All I can say is, imagine a beard trimmer, and each blade of the comb is the size of manhattan, each with tiered 'hoods."

- Paul Russel

100_forecity (or more simply, Forerunner City) was a level that was worked on during the development of Halo 3, but was ultimately cut from the game. The level was to follow on from 090_alpine, and was ultimately combined with 090_alpine in the final release of the game to form the mission The Covenant. The level is famous for its distinctive Forerunner structures, more commonly known by the nickname The Lost City, or more jokingly, "Forerunner Condo" to Bungie and "Cuesta Verde phase 4" to Vic DeLeon.

Forerunner City was given some limited development during Halo 3's production, with basic mission layouts and 3D models generated, though these were largely scrapped once the level was merged to become The Covenant. Many of its intended plot beats were adapted into the final game mostly-intact (albeit polished). In the final game, the remnants of Forerunner City can be seen in the final encounter on The Covenant - particularly the sections inside the Citadel at the end of the level. Most of the plot information about the level comes from a first-draft script uploaded online by campaign design lead Rob Stokes.

Overview
Forerunner City received some limited development and 3D prototyping in Halo 3's development before being combined with Alpine to form The Covenant. An initial script pass was done by Rob Stokes, with visual look-development done by Paul Russel. During production, Russel's 3D environment grew so large that "it could be a game in itself". Nonetheless, it was to have been a fully-playable level, with Russel's 3D blockout used as the basis for a level layout plan done by Stokes.

As part of Russel's development process for the art in the level, he tried to use the city's architecture to showcase values held by Forerunner society and how they might have lived their daily lives. Vic DeLeon also worked on the level, and further elaborated that their goal was to create something more than "just cool shapes with mysterious purpose," creating something that told a story. Russel stated that in total, there "were probably 10 different versions of the city."

Once the architectural blockout was made, it was passed on to Vic Deleon, who populated the area with vegetation, entropy, and lighting. They worked on the project for around three weeks alongside a cut level named "Tsavo Township" before being moved to making multiplayer maps for Halo 2 DLC. By this time, the fiction surrounding the structure was that it was to be a housing complex for Forerunner scientists living on the ring, possibly the Librarian's team. The idea of this iteration was to design the abandoned living space with a courtyard, one that had fallen into disrepair. Another developer, Dan Miller, stated that the level was cut as the development team felt it would give too much away about the Forerunners and their mystery.

Developers known to have worked on Forerunner City include:
 * Rob Stokes (mission design and script)
 * Dan Miller (level designer)
 * Paul Russel (3D environment art)
 * Vic DeLeon (3D environment art)
 * Isaac Hannaford (concept art paintovers)
 * Lee Wilson (storyboards)

Plot
This section summarizes the plot of the level, based on the first draft of the script submitted by Rob Stokes for further editing later on, and the mission design documentation posted on his website.

Background
During prior missions, forces from (replaced by  in final release) observed that the Prophet of Truth had moved his forces behind a large energy barrier preventing UNSC access. In the previous level 090_alpine, John-117 had successfully attacked the barrier towers preventing access before witnessing the arrival of the Flood-infested High Charity. The infested station crashed on the Ark and began to spread Flood across the megastructure.

100LA_CITY_GATES
The first section of the mission, titled "City Gates" in the script, sees Master Chief enter the eponymous Forerunner City to find the control citadel for the entire Ark (referred to in the script as Waypoint). In this opening section, the player leads an attack force through the city's ruins toward the Citadel, facing off against Brute forces loyal to the Prophet of Truth. During the level, the Chief would receive a transmission from Miranda Keyes with a mission briefing, though it would be cut short abruptly due to Miranda and her people coming under attack - leading to Miranda's capture later in the level.
 * 100LA01 EXT. ALPINE

During this section, level design documentation notes that as the player fights on, Flood spores and tendrils would be visible beginning to creep up the structure and infect it. During the vehicular combat of the mission, the player would drive a Scorpion tank alongside allied UNSC and Elite troops, facing off against Brutes in the streets. The combat would feature massive three- and four-way battles between the player, Covenant, Flood, and Sentinel forces. Halfway through the mission, the tank convoy would be stopped by a barrier and forced into an engagement on foot, seemingly inside the vegetative and overgrown spaces shown off by Vic DeLeon (point C on the design document).

These near-final iterations of the level were done by Vic DeLeon in 2005, running in the "Halo 2.5-3" engine. They seemingly depict the location at point C.

Moving back outside of the overgrown structure, the player would be faced with a Flood-infected Scarab walker. Luckily, a number of Guardian Sentinels would show up and help to destroy it, presenting the player with an opportunity to drive the Scarab and use its main gun on the gates leading outside of the courtyard. This would lead to a section labelled on the design layout as the "Most massive Scarab battle of all time!", with the player fighting two Scarabs in their own Scarab. The Scarab fight is located just outside of the Citadel, as in the final game, leading Master Chief and the Arbiter to then enter the Citadel.

The script picks up again inside the structure, the two would be greeted with billowing Forerunner tapestries and the mad ramblings of the Prophet of Truth: "The demon has failed. The traitor has failed. Yet I have succeeded. It is close now! The faithful can feel it! and the faithless are too late to stop me!"

The player would then reach a gravity lift and press X on the controller to activate a cutscene.

100LB_MIRANDA
The cutscene inside the Citadel would play out much akin to the final game's, albeit with less refined dialogue. The Arbiter and Chief enter the foyer and are subjected to see a live feed of Truth activating the Halo Array. He calls on his Brute bodyguards to bring Miranda - now captured - from the shadows with the intent of activating the rings. However, she struggles against her captor and is able to grab the Brute's pistol - holding it in the air and turning around. As the Brutes close in around her, Truth hides behind them. Miranda realizes that they need her to activate the rings and starts to bring the gun to her own head, only to be stopped by Truth. Truth grabs her by the throat and then brings her over to the activation console - using her to activate the rings in much the same way as he uses Johnson in the final game. Finally, he then snaps Miranda's neck, killing her.

The activation pulse of the rings begins in the foyer, where the Arbiter and Master Chief are, with Master Chief staring at the image of her dead body before the return to gameplay. The player progresses through the Citadel facing down Truth's honour guard, with the Flood additionally pouring in and attacking. Curiously, the Flood do not attack the player and instead let them pass - with the Gravemind heard talking through them that they will allow them to pass - in recognition that a human's hand is required to deactivate the Halos. The player ascends the tower, and finally presses X to open the doors into the central chamber and play a new cutscene.

100LC_CONFRONT_TRUTH
As the player enters the control room, they're greeted by a very different site to what they saw on the screens. The Brute bodyguards are already dead, and are already displaying signs of Flood infection. The Chief and Arbiter move through the carnage, with Chief stopping by Miranda's body to kneel and close her eyes. The two then spot Truth huddled on the ground near the control console. The Arbiter surges forward, unable to contain his rage, but is stopped by the Master Chief due to something being not right. Truth begins to speak and requests the Master Chief's help to fire the rings and commence the Great Journey, but midway through his speech he is interrupted by the Gravemind. Flood tentacles can then be seen bursting from his chest and infecting him. Truth and the Gravemind briefly battle to speak, with Truth pleading the Chief to be allowed to ascend, while the Gravemind finally takes full control of his body and orders the Chief to stop the firing.

Unlike the final game in which the Arbiter is the one to silence Truth, the player starts gameplay again with their reticule pointed at the Flood-infected Truth. They dispatch Truth, and are beset upon by Flood forms from the shadows. As the Flood advance, the player is pushed into the dark bowels of the Citadel - where they notice blue shimmers in the air. Eventually, they become trapped in a dark room facing off against waves of Flood, with the final cutscene of the level starting once the final wave is defeated.

100LD_FLOOD_REVEAL
With a brief respite in the fighting, Chief, Arbiter, and Spark ponder that the Flood is now truly unstoppable - they are on the Ark and the Halos cannot be fired anymore. However, Chief begins to see flashes of Cortana around him, and finds himself at a dark corridor. He heads down the corridor and finds himself at a console with a brief apparition of Cortana standing next to it. A single button can be pressed, which sees the walls of the chamber begin to unfold and reveal the Ark's core around them. A new Halo ring then arises from the foundry as in the final game. The dialogue plays out mostly the same, with Chief and Arbiter agreeing to light the ring, Spark flying off into the distance, and Chief making the decision to retrieve Cortana from the remains of High Charity.

What would have followed next would be the level highcharity, though in the final game this level was cut and replaced by the level Cortana.

Legacy
The final iteration's exterior appears to have influenced the design of the final game's Cartographer: the forward half of the city, especially its spire, is virtually identical to the map room's exterior structure. A building identical to the third iteration was also featured in the Halo Legends episode Origins.