To all those who found Halo 2 to be lacking story-wise (as I did) a reason.
This is long, but any true Halo Fan should find it HIGHLY fascinating...
The following is all true, based on documentaries, articles, interviews, the special DVD that came with the game's Silver Edition, and basic perception.
Roughly 7 months before E3 2003, Bungie decided they would shock the world with an intense footage of live, actual gameplay that blew everyone away. Unfortunately, 7 months before E3 2003, all they had finished making so far was the game's basic outline (story and content-wise) and an experimental version of the game's engine, all of which took about 5 months in itself. Nevertheless, they spent the next 7 months solely on that 10 demo so that it would hype us out of our minds for the actual game. Anything they could think of that seemed cool, they threw into the demo without thinking about any consequences it may have. Like people thinking it would be in the game. They were just too excited to care.
Ultimately, finishing the demo took up all of their 7 months of work time.
After Bungie hyped the world out of its mind with their undeniably awesome demo, they came back and realized they had made a mistake that not even the public or gaming press would think a game company could make... which officially became known as, based on hard stats, "The Greatest Upset in Gaming History".
They had wasted the last 7 months of work. Completely and 100%. They realized they didn't have a level. They didn't even have a part of a level. What they had was a demo, that ran on an experimental engine that ultimately could not work with the Xbox, and none of it could be implemented into the actual game. For the next TWO months, I kid you not, Bungie studios was practically empty because they were so confused on what course of action to take.
Those 2 months dwindled away. That's when Microsoft showed up...
Microsoft, being fair and rational, inquired as to why the hell Bungie had been screwing around with Halo 2 for 1.5 years but still seemed to have no useable material. Who knows if Bungie leveled with Microsoft and admitted they screwed up, or if they hid the truth somehow. The fact was, the hype for Halo 2 had been set with an actual playable demo. The public would not stand for waiting much longer after seeing something that made the game look so... complete. In all rationality, a good game takes about 1.5 years to make. It had been almost 2 since the public thought Halo 2 was in the works. So Microsoft did what it had to do. It gave Bungie a deadline that would wind up as their death sentence. They were given 10 months to finish the game before Microsoft demanded the discs be made and shipped.
They hadn't even started making the actual game...
For ten months, Bungie studios sacrificed every fiber of their beings to make the game. They did not go to their homes after work. They designed and programmed for 18 to 20 hours a day, falling asleep on their desks or on beanbags. They rushed the game furiously. Slamming it together piece by piece, hoping things at least functioned without a total crash.
And as the leader of Bungie said, "At that moment, Pandora's Box was opened...".
Literally 75% of what Bungie had originally intended to be in the game, had to be scrapped. It was absolutely the only way to finish the game on time. If anyone wants me to, I can develop a list of what was promised in the game that was ripped from it.
The worst part of it all, was that even the original intended storyline had to be mutilated. Anybody remember the original Halo 2 Teaser where the MC jumped out of a space station? Think about what we saw happening to Earth in that trailer. Or watch it again. What do you notice?
Earth... is in flames.
Most people have forgotten that the trailer and demo of Halo 2 both gave a direct impression that the game would contain the first stage of THE LAST BATTLE FOR EARTH. ALL ACROSS AND OVER EARTH. Think of the demo. Human bombers bunker-busting giant covenant artillery, Jackals marching in Rusty Nails"
I tend to believe this, particularly as Bungie are now working in "opposite" conditions: No defined release date, they are out-sourcing the teaser/trailer responsibilities.
Also, mistakes made in Halo 2 seem to have been taken to heart. Earth is central. Don't expect a trunkated earth-campaign. There is no sign that there will be any other playable race (maybe I'm just being naive). Stronger story devices, in that the story, at least the emotional focus, will utilise flashbacks to give the Masterchief a greater human element. This possibly because he will die in Halo 3.