Few video games inspire the reverential awe that Halo does.
By Alfred Hermida
BBC News Online technology editor
The title for Microsoft's Xbox was critically acclaimed when it first appeared in November 2001, going on to sell more than four million copies.
Much more effort has gone into the multiplayer aspects of Halo 2
With the release of its sequel just a few weeks away, speculation is rife about whether Halo 2 will live up to the hype.
The team behind the game, Bungie Studios, has remained notoriously tight-lipped about what it will be like.
"It picks up where Halo left off," said Pete Parsons, Bungie studio manager, "but we don't want to give out too many details about the story."
In a sense, Halo 2 promises more of the same, but better. Gamers get to play as Master Chief, the selfless hero who saves the Universe from the scourge of the alien race, the Covenant.
This time round its personal, with the fate of the Earth at stake.
"You are involved in mankind's plight to save itself," Mr Parsons told BBC News Online.
"Your job is to apply the Master Chief boot to kick Covenant ass."
An old friend
Bungie have had a team of 55 people working on the game for at least 16 hours a day to meet the release date of 9 November in the US and two days later in the UK.
As well as working on better visuals, the developers have also sought to address one of the big complaints about the original game.
"Repetitive levels were a problem in Halo 1," admits Mr Parsons. "Now we've had the time to make sure we don't have so many repetitive levels."
But Bungie is aware that making too many changes could alienate the loyal following the game has attracted.
"We are trying to keep the same magic," said Mr Parsons. "The aim is to feel like you are becoming reacquainted with an old friend."
One of the major changes is the ability to fire two weapons at the same time. This dual-wielding feature forces players to make choices about the weapons they carry and how they are used, as some combinations work better than others.
The weapons themselves have been tweaked to balance out their power, and there are a couple of new additions, such as a deadly Covenant sword.
The big change in Halo 2 is the emphasis on online gaming via Microsoft's subscription-based network, Xbox Live.
This was absent from the original, though some hardcore fans found ways around this by using PCs to connect an Xbox to the internet.
Gamers can use two weapons at the same time
"Nobody expected the multiplayer to take off like it did," said Mr Parsons.
Multiplayer is central to Halo 2. So far Bungie has only allowed a handful of people to play some of the forthcoming maps.
The three maps it has so far shown off are far more complex than in Halo 1, offering a taste of engaging and hotly-contested firefights to come.
In the smaller, closed environments, the action is frenzied and intense, partly due to the dual-weapon wielding feature.
Bungie has worked on a system to ensure you can play against people with similar skills.
This was one of the weaknesses of the PC version of Halo. It offered online gaming, but no way of distinguishing between hardcore, experienced players and newbies.
In an attempt to enhance the online experience, Bungie has also created what it calls a Party system.
The sword is a new and lethal weapon in Halo 2
"It is a way of creating a virtual couch," explained Mr Parsons.
Essentially this allows a group to move online as a team, so that you can move from game to game with your friends.
"This was a massively difficult thing to do," said the Bungie spokesman. "This became a really important thing to do.
"It became critical, because if I don't feel that I'm playing with my friends, it sucks."
The multiplayer maps will also feature a range of different game modes - one of a variation on the bomb game found in the popular online game Counter-Strike.
Some 8,000 people have been testing Halo 2 ahead of its November release.
Bungie is reluctant to talk about what happens once the game is out of the way. There has been talk of a film version and the developers appear to have enough material for a celluloid Master Chief.
"We have several 100 years of Halo fiction laid out," said Mr Parsons.
But as to the notion of transferring this to the big screen, he said: "Maybe some day.
"There certainly has been interest in the idea, but it is not something we are thinking about."
Instead Bungie seems to have set its sights on a new game, though Mr Parsons shied away from giving any precise details.
"After Halo 2 we are planning to do something different. We will do something else and we have a few ideas."