Alpine (cut Halo 3 level)

Alpine, known internally as, was a planned level during the development of Halo 3 - though was ultimately scrapped for final release. The level was intended to follow on from Guardian Forest and by succeeded by Forerunner City - though ultimately elements from all three levels were combined to form the final game's level The Covenant. In The Covenant, the majority of the first half of the level follows the ideas first established for Alpine, with the latter half taking more inspiration from Forerunner City.

The scrapping of these levels was done fairly early on in development. However, the level is present in a first draft of the game's script written by campaign design lead Rob Stokes. This script provides the majority of known narrative information about Alpine, alongside a handful of planning and design documents posted by Stokes on his personal website.

Overview
The presence of  in Halo 3 remained a mystery within the Halo community for some time prior to the work posted by Rob Stokes. In the base Halo 3 file structure, levels are sorted into folders based on their map file name, with a notable gap between  (The Ark) and   (The Covenant) observed by modders. The later discovery of a texture file in an  (Guardian Forest) folder narrowed down the missing levels to just the mystery   - something which would remain a mystery until the release of the Halo 3 Mod Tools in 2022. Later testimony from level designer Dan Miller would confirm the existence of, with more extensive details provided in the documents uploaded by Rob Stokes.

Developers known to have worked on Alpine include:
 * Rob Stokes (mission design and script)
 * Dan Miller (level designer)
 * 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
Having been rescued from Strato-Sentinels in the Guardian Forest by a Pelican, Sgt. Johnson, John-117, and the Arbiter head towards a barrier preventing them from reaching the Prophet of Truth.

090LA_ALPINE_ARRIVAL
The Pelican approaches the barrier as other Pelicans line up in formation behind it. These Pelicans fly past the energy barrier and its accompanying pylons, preventing their access to Truth. Johnson gives a little hearty speech to the Marines accompanying him and John before the Pelicans descend.

The player, sitting in the rear of the Pelican, would watch as the others land and deploy various forces before finally being able to disembark themselves. They would then go on to breach and deactivate two of the towers to the barrier. After deactivating the second barrier and while they head back towards where they came, they were to receive a garbled message from Cortana.

090LB_HC_CRASH
After receiving the Cortana message, the player would be greeted by a Marine attempting to provide a report on Truth's forces behind the barrier, only to be interrupted by the sight of a flaming chunk of debris hitting a nearby mountain, causing an avalanche of snow to spill into the valley. Everyone would then look up to witness as more flaming chunks fall from the sky, followed by the arrival of High Charity which would fly overhead before crashing on the far end of the barrier.

For the rest of the level, the player would have to now contend with both Covenant forces and the newly-arrived Flood while badly-damaged Elite ships pursuing High Charity from Earth would arrive overhead. After clearing out the forces outside the final tower (with one planned encounter being a three-way battle between the player, The Flood, and a Scarab) the player would enter the final tower and deactivate the last part of the barrier, allowing the UNSC and Elite forces to proceed to the Forerunner City.