Phaser said:
There was tons of planned stuff that didn't make it into the game. To start with, the infamous E3 in-game footage of New Moombasa was completely changed.
That level was incredible. Better than everything in Halo 1. It's a shame that didn't make it into the final game, but there was a short homage in one level that lasted about ten seconds.
The game originally was slated to have a lot more vehicles - as far as I recall, there were at least four different versions of the Warthog and a new weaponless but ultra fast ATV-type vehicle.
I remember that. There was a vehicle even specifically designed for snow levels, even though the final game didn't actually
have a snow level. (Well, there was that section of the one, but as it sucked so much it doesn't count in my book, not when levels like "Assault on the Control Room" exist).
There was also this Batmobile-looking Covenant vehicle that I was expecting to see, a picture was leaked or by someway discovered alongside the leak of those bug-type aliens. The bugs made it in, but the awesome vehicle didn't.
The designers said that they also had a whole mission take place on a moon, complete with less gravity etc.
Again, an element of this did make it into the game and absolutely not as cool as what was scrapped. There's a part in the first level when you're walking on top of your space station, that was really lame.
The levels were planned to be more along the lines of the first game's Silent Cartographer level, in that you'll be fighting alongside friendly A.I soldiers quite often right in the middle of huge warzones ala Saving Private Ryan.
That's something I felt was far different from the first Halo. Halo 2 definitely lacked the amount of "platoon" missions that Halo 1 had. The one that stands out most to me is in the inside of that big Covenant city, but that was nowhere near the standards set by Halo.
And last but not least, Jason Jones highlighted that a big part of Halo 2's gameplay and story was about "taking the fight to the Covenant" in full-scale war.
At this point, I hope the team pulls a Kameo, upgrading the graphics sufficiently, and then having 5000 people onscreen. I know just from Kameo, the power of the 360 could place you in a warthog running over thousands of Covenant "on their own turf", we'll just have to see what Bungie wants.
Judging from that last one, I can't help but come to the conclusion that Bungie hit the reset button on Halo 2's development halfway through when they realised that the simply can't pull it off (this is very much apparent in the Bonus DVD features) and instead, concentrated squarely on multiplayer features.
And I'd really like for them to bring in everything they cut out of Halo 2 into this one. It was Jamie Greissemer I believe who said that they in fact did have to start over, just because everything they were working on up to that point had no cohesion. I'd like for them to revisit their unfinished work and squeeze it into the Halo 3 campaign. I would still like to play the E3 2003 New Mombassa level, as well as see the Chief with even more fidelity than he was first shown with. All I can do is hope, or just expect Bungie to make something even better.
The ending of Halo 2 also screams of the "back to square one" syndrome in that it is quite obvious that the third game will also start like the second one, with the Covenant launching a full-scale assault on Earth and the Master Chief diving in with guns blazing once again, and so, in Halo 3, we'd see what Halo 2 really would have been.
It's true Halo 2's campaign was rather inconsequencial, even the non-Arbiter parts. However, despite the game's development hell, it's still surprisingly one of the best games on the Xbox, and of this generation. It's clear the multiplayer half of the game didn't run into these problems, because there's not to much wrong with the multiplayer technically (it's the players and cheaters who mess it up).
But the important things are that Bungie has learned from this, has moved to a new location, and has expanded it's team sizes. Halo 3 ought to be pretty awesome.