Halo: The Master Chief Collection includes Halo 2: Anniversary and remastered versions of Halo: Combat Evolved Anniversary, Halo 3 and Halo 4. Halo: The Master Chief Collection is the first time that the entire story of the Master Chief is on one console. It features all campaign missions and all multiplayer maps from Halo: Combat Evolved, Halo 2, Halo 2 Vista, Halo 3 and Halo 4, plus access to the live-action digital series Halo: Nightfall and access to the Halo 5: Guardians multiplayer beta.
Halo: The Master Chief Collection features a unified user interface which allows users to jump between the different games seamlessly. This allows for multiplayer playlists that feature maps from all five games (Halo 2: Anniversary has multiplayer which is unique from that of the original Halo 2 multiplayer which is also a part of the collection).
The collection introduces the idea of Campaign Playlists which are lists of campaign missions (from any of the four games) along with other settings (such as difficulty level, skull selections and scoring settings). Example playlists include: Tanks Tanks Tanks (all missions where players control a tank), Me and My Hog (all missions where there is a driving section that features warthogs), Speed Runner's Choice (a selection missions specifically for speed runners) and The Legendary Master Chief Saga (the entire campaign of all four games on LASO [Legendary difficulty with All Skulls On]).
Halo 2: Anniversary is a re-release of Halo 2, intended to celebrate the tenth anniversary of the game. The anniversary edition comes with the same single player campaign, the only difference being that the player can switch between the graphics engine used in the original Halo 2 (for identical graphics to the original), or switch to the a newer graphics engine based off the one used in Halo 4 (for more modern graphics) at any point during the campaign, even mid session. The campaign also supports cooperative gameplay (both split screen and online).
As previously mentioned, the multiplayer portion of Halo 2: Anniversary is split into two sections. One being the multiplayer from the original game unchanged (running on its original engine) other than that it runs at the modern 1080p 60fps. The other being an updated version of multiplayer which has remastered graphics and was built off the Halo 4 multiplayer engine, but has been adjusted to have a similar play experience to Halo 2 with some new gameplay features. The updated version of multiplayer also has features introduced later in the Halo series, such as Forge, File Sharing and a Theater mode.
The remastered versions of Halo: Combat Evolved Anniversary, Halo 3 and Halo 4 run on adapted versions of their original engines, which means that everything is the same as when they were released other than that they run at the modern 1080p 60fps. For the first time, Halo: Combat Evolved will have online multiplayer through Xbox Live (unlike in Halo: Combat Evolved Anniversary, this multiplayer will run on the game's original engine).