Bungie has admitted that elements of Halo: Reach 'will upset hardcore fans' of the series' source material.
However, the studio has pledged that the majority of game will 'delight' die-hard fans of book The Fall Of Reach - and that it had made the title with the affection for the novel very much in mind.
Creative director Marcus Lehto added: "We are very sensitive to the Halo canon, and we are careful not to be stomping on the Halo timeline. We're playing to the events of the book, and while it's not the gameplay version of the book, that story is taking place in the background. We're following one isolated part of what's happening on Reach."