[CAMPAIGN]
-Atleast one living Foreunner will make an appeareance in the campaign.(probably the Didact)
-UNSC will show up with some new toys.(The Infinity, Spartan IV’s, New Guns)
-We will be fighting more advanced Flood, human separatists, some species from the covenant, along with something new.
-New Graphics Engine combined with length will force campaign to have it’s own disc.
-Guilty Spark comes back from the dead.
-4 Player drop in/out co-op campaign similar to Gears of War 3.
-Scoring turned on will have a deeper system with more ways to earn points/medals.
-Tons of hidden things in campaign(Skulls, Terminals, Easter Eggs)
-Will feature support for Kinect, 3D, WP7, and anything else Microsoft is pushing.
[MULTIPLAYER]
-None of the maps that ship on the multiplayer disc will be remakes, instead we will get a retro map pack shortly after release that will feature some of the iconic maps.
-Clans will return and be the central focus for competitive play.
-Number of players in a single match will be greater than 16.
-Will feature tons of unlocks(armor, weapon skins, nameplates)many times what reach has.
-Skulls or similar gameplay altering modifiers will be added as an option to multiplayer.
-Ranking, Commendations, and Medals will be overhauled and expanded.
-Firefight 3.0 will have features closer to Horde from Gears of War but also new ideas.
-Invasion, Infection, and Griffball will all return in Halo 4 matchmaking.
-Forge 3.0 will have so many options people will be blown away.
-Both equipment(Halo 3) and armor abilities(Halo Reach) will be in Halo 4 but not in every game type.
-Elites will not be playable at all in Halo 4.
[Miscellaneous]
-Halo 4 will come in normal and legendary versions.
-Feature the most DLC of any Halo game.
-Will also offer a season pass for DLC or launch a subscription service with Halo 4.