Halo 4's story follows a genetically enhanced human supersoldier, Master Chief, and his artificial intelligence construct Cortana, as they encounter unknown threats while exploring an ancient civilization's planet.

The player assumes the role of Master Chief who battles against a new faction that splintered off from remnants of the Covenant, a former military alliance of alien races, as well as a new enemy: mechanical warriors of the Forerunner empire known as the Prometheans.

In the developmental process, 343 Industries decided to explore the Forerunner fiction within the Halo universe, leading the team to design a new setting, enemies, and main antagonist.

A goal for Halo 4's story was to incorporate more human elements; to achieve this, the developers chose to delve more deeply into the relationship between the two protagonists, Master Chief and Cortana.

[2] The game sees the return of the alien species who were formerly members of the Covenant as foes, and introduces a new type of enemy called the Prometheans, which are Forerunner artificial intelligence (AI) constructs.

[24] The human supersoldier Master Chief Petty Officer John-117 and his artificial intelligence companion Cortana, were instrumental in stopping the Halos from being activated, sterilizing the Flood outbreak before they could menace the galaxy once again, and defeating the Covenant resulting in the end of the war.

Chief and Cortana recommend attacking the Didact while he is vulnerable, but Infinity captain Del Rio orders them to destroy the gravity well so their ship can escape.

Sarah Palmer, commander of the Spartan-IVs, deploys Spartan squads to clear out Jul 'Mdama's Covenant and Promethean forces in Requiem's interior in order to set up research bases.

[40] Following Halo 4's announcement, O'Connor reported that both Master Chief and Cortana would undergo "radical" changes in appearance for the game, some of them attributed to better graphics and others to story elements.

[42][45][46] The main goal when designing their appearance was to make them resonate with the player, and evoke the image of the Forerunner architecture and language that had been portrayed in previous Halo media.

[32][49][50] The majority of the game is lit statically using lightmaps; this allowed the art team to achieve realistic lighting effects with full global illumination and ambient occlusion.

Axis worked with Glasgow-based audio post production company Savalas on sound design and the final mix for the Spartan Ops cinematics.

To save time and expense using traditional motion capture methods to animate the 3D characters, The Sequence Group used twin Microsoft Kinect infrared sensors to create a home-made solution.

[61] Sotaro Tojima, best known for his work on Konami's Castlevania: Circle of the Moon and Metal Gear Solid 4: Guns of the Patriots, served as Halo 4's audio director.

[68] Voices for new characters include Mark Rolston as Captain Andrew Del Rio, Darren O'Hare as Thomas Lasky, Jennifer Hale as Sarah Palmer, Adrienne Barbeau as Dr. Tillson, Keith Szarabajka as the Didact, Travis Willingham as Jul 'Mdama, and Lori Tritel as the Librarian.

[73] On January 19, 2012, McFarlane Toys announced that they would be creating action figures for Halo 4, bringing new characters, weapons and vehicles from the video game to the fans.

[13][85] In the United Kingdom, a promotion ran from September 24, 2012, until December 4, 2012, where purchasers of Mountain Dew were able to redeem codes to have a chance of winning copies of Halo 4, Xbox 360 avatar items and a trip to Seattle to attend a tour around the studio of 343 Industries.

[87] Microsoft also partnered with Pizza Hut branches in the United Kingdom; people who entered the contest via an official website had a chance of winning Halo 4-themed prizes.

[91][92][93][94] A nearby countryside had a United Nations Space Command military camp installed and Balzers Quarry was transformed into a battleground where fifteen actors played out a two-hour-long adventure.

[10][39] The plot is centered around the character Thomas Lasky, who appears in the video game, he is primarily portrayed by Australian actor Tom Green in the live action series.

[105] In October 2012, visual effects company Framestore assisted advertising agency McCann London in producing live TV adverts for Halo 4.

It was also announced that Microsoft would be releasing a standalone Xbox 360 Halo 4 Limited Edition wireless controller featuring a different design to the one included in the console bundle.

[115] On the evening before the release of the game, a fifty-foot diameter illuminated Didact glyph was flown by a helicopter over the River Thames in London, from the Greenwich Peninsula to Tower Bridge.

[117] Following the release of the game, New Zealand censors declared many copies of Halo 4 illegal, after deciding to label it with an R13 rating, restricting it to buyers aged 13 and over.

[136] Spartan Ops went on a mid-season break that December and resumed on January 21, 2013; the back half of the season was made available as a free download from the Xbox Live Marketplace.

[144] The tournament finals took place on September 1 at the 2013 Penny Arcade Expo; the event was streamed live and was hosted by Larry Hryb, Blair Herter, and Jessica Chobot.

"[19] Wesley Yin-Poole of Eurogamer remarked that although he was initially skeptical of changes being made to the formula, 343's greatest achievement was managing to stay true to what Halo is.

[155] IGN's McCaffrey praised the game's lighting, movements, animations, and lauded the campaign for its pacing, "deftly mixing on-foot combat, vehicle sequences, quiet story moments, and key Chief-and-Cortana interactions."

[152][156] G4 reviewer, Adam Rosenburg, also stated that while the soundtrack had some memorable moments, he was disappointed that composer Neil Davidge had chosen to ditch the familiar theme of previous games.

[154] CVG's Gapper stated that the new scoring system alone made Halo 4 multiplayer the best in the series, emphasizing that recognition for assists and completing objective tasks was a positive change.