According to GamesRadar.com, it was revealed at Gamescom that Halo 5: Guardians will feature a campaign that will be twice as long than Halo 4’s.
Along with the size of the campaign, Halo 5: Guardians will also feature all three worlds for players to explore: The human world (presumably, Earth), The Covenant world and the Promethean world (GamesRadar calls it the ‘Fallen’ world). The length of the game should help players get a proper handle of the two different teams featured in the game: The Blue Team featuring the Master Chief, and the Red Team, featuring Halo’s new protagonist, Spartan Locke.
It was recently announced that while Halo 5 will feature four-player co-operative play, the game itself will ship without split-screen support; a first for the Halo series.
Halo 5: Guardians will be released exclusively for the Xbox One on October 27th, 2015.
Source: GamesRadar.com