Oh, the E3 2003 Halo 2 presentation? It was made on an engine that the Xbox literally couldn't run and just to get the demo to work they had to axe everything that is out of view. They came back from E3 and had to scrap that entire build and pretty much make the game again on a brand new engine in the next year and a half to meet the release deadline.
Literally a year before launch the team had no engine, environments that couldn't possibly work in any engine, features that were only half-implemented, a story that would eventually require Halo 3 to finish and a multiplayer mode that would have to be scrapped.
Halo 2's development was so fucked lmao