Halo 2 E3 demo

Halo 2 E3 Demo eG2m4_XVLDM The Halo 2 E3 Demo was a real-time demonstration of early plans for Halo 2's Outskirts level.

It was shown at E3 2003, and showed some designs for Halo 2, including ODST's, Battle Rifles, (which were originally going to be single-shot), Dual-Wielding, SMG's, Brutes, and many other things.

Differences with the final Game
The demo had a vastly different storyline from the final game. Much of it was essentially rewritten to change the events.
 * The New Mombasa Orbital Elevator is nowhere to be seen. Instead, a massive building complex dominates New Mombasa's skies.
 * The Pelican Master Chief lands in is not destroyed, instead it lands normally and disperses its troops without a problem.
 * Master Chief passes through a battlefield hospital before engaging Covenant ground troops in combat.
 * Sergeant Banks is an injured marine who gives Master Chief his SMG, introducing the Dual Wielding feature.
 * Brutes attack Earth side by side with the Elites.
 * The Chief is trying to destroy one of many landed CCS-class Covenant battlecruisers, instead of a single Assault Carrier.

Other Links
It can be viewed here: http://files.mythica.org/halo/halo2_e3_realtimedemo_hires.mov Or downloaded here: http://www.bungie.net/Games/Halo2/page.aspx?section=AudioVideo&subsection=GameVideos&page=1