It’s been nearly two decades since Bungie released its first gameplay demo for Halo 2 at E3 2003, drawing massive cheers from the live audience by showcasing Earth City for the first time and demonstrating some of Master Chief’s then-new skills, such as dual wielding, but while the level never made it into the final version of the game as depicted, Halo 2 fans will soon be able to actually play it.
An extensive article that 343 Industries shared this week regarding prerelease and development content that was cut from earlier Halo games can confirm that the developer is working on a rebuild of the legendary and infamous Halo 2 E3 2003 demo, one that will be playable in the modern retail version of the acclaimed game.
343 can’t promise when it will be released or if it will even be playable on platforms aside from PC, but it could be a while before it surfaces due to the complexity of the project, which includes “3,400 lines of barely documented haloscript” that must be translated into the modern engine.
I can confirm we are working on a rebuild of the original E3 Earthcity scenario that makes it playable in modern retail Halo 2.
This was NOT a trivial process, and we should probably layer on a whole page of caveats that come with taking a demo map for an engine that no longer exists and getting it to not blow up the current lightmapper (among other issues that come from letting people go into areas that were never intended to be seen).
In many ways this is harder than Alphamoon to work on, as it was never made to be played “off script.” Oh, and the scripts. Well over 3400 lines of barely documented haloscript originally written under an insane time crunch almost two decades ago, which itself was made to work around various bugs of the engine at that time. Not a joy to decipher and translate into the modern engine, to say the least.
Source: Halo Waypoint