The game's campaign follows the human supersoldier Master Chief and his fight against a mercenary organization, known as the Banished, on the Forerunner ringworld Zeta Halo.

Infinite was intended to release as a launch title for the Xbox Series X/S, but was delayed in August 2020 after its gameplay reveal in July 2020 drew negative feedback from both critics and Halo fans.

[5] The campaign mode's semi-open world structure allows players to freely explore parts of the ring-world Zeta Halo setting, which are segmented off from each other and initially impassable.

[5][6] Other points of interest found across Zeta Halo's surface include "high-value targets" to eliminate, Marine squads to rescue, and Banished propaganda towers to destroy.

[9] Infinite's multiplayer component features deathmatch, capture the flag, and other modes played in standard 4-versus-4 and Big Team Battle variants; the latter bumps the player count in matches up to 24.

While defending the ship's hangar bay from multiple raiding parties, the Master Chief is caught off-guard by Atriox, the leader of the Banished, and is subsequently defeated in a one-on-one duel.

Despondent Pyre attempts to warn Master Chief of a threat contained on the installation, but is destroyed by the Harbinger, an alien awoken by the Banished.

If the game is finished on Legendary difficulty, the scene features dialogue between Despondent Pyre and a Forerunner official about the imprisonment of the Endless.

When Despondent Pyre states that she cannot oversee the study of the Endless alone, the Forerunner replies that the AI Offensive Bias has been deployed to assist her.

Meanwhile, during a reconnaissance operation to a former UNSC shipyard on the planet Camber, Spartans Sigrid Eklund and Hieu Dinh discover that the Banished have created their own AI construct, named Iratus.

Agryna's plan eventually succeeds and Iratus, along with a complete archive of the Banished's operations on Camber, is secured, saving Dinh's life in the process.

Some time later, Dinh—alongside an unnamed Spartan recruit,[e] discovers an entry point to a secret underground base, built by the Office of Naval Intelligence (ONI) at the beginning of humanity's war against the Covenant.

[24] While reception to Halo 5 was overall positive, the campaign received criticism for not including enough of Master Chief; 343 Industries promised to refocus on the character going forward.

[67] On August 11, 2020, it was announced that the game had been delayed to an undefined date in 2021,[68][69][70] due to a range of factors impacting development, including the COVID-19 pandemic.

[77] A technical test for the multiplayer portion of the game ran from July 29 – August 2, 2021, where select members of the Halo Insider Program could compete in teams across three maps against bots in 4v4 Slayer mode.

TAG DESIGNATION: FOE",[87] which featured an audio clip of an anonymous character who represents the Banished, a faction introduced in Halo Wars 2.

[88] Among the merchandising tie-ins for the game was Monster Energy Drink, a "Moa burger"-flavored version of Pringles, and Dr. Squatch "Spartan Soap".

[89][90][91] Coinciding with Infinite's gameplay reveal was a trailer, "Step Inside", produced by 215 McCann, who had previously worked on the "Believe" campaign for Halo 3.

The spot, showing Master Chief's armor being made, was the kickoff to a wider campaign, "Become", which focused on how the events of the games are shaped by ordinary people in the Halo universe.

[94][95] On August 25, 2021, a CGI trailer for the first season of Infinite's multiplayer mode was released, focusing on the backstory of the new character Commander Agryna in an occupied London.

Other tie-in hardware included hard drives, keyboards, mice, and a limited number of Halo-themed Radeon RX 6900 graphics processing units.

"[3] Aaron Greenberg, general manager of Xbox marketing, responded in an interview with Inside Gaming: "Listen, we're in the middle of a global pandemic.

[98][99] Narrative experience director Dan Chosich tweeted: "I want you to know your voice matters + is heard [...] I always want to live up to the legacy that Bungie pioneered.

[101] When 343 Industries released improved gameplay videos closer to Halo Infinite's release, they included shots that purposely showed an improvement in visuals and appearance of "Craig", which character and combat director Steve Dyck and character art lead Bryan Repka considered a "glow-up", and that the community response to "Craig" was "one of the factors in gaining some more time to finish work and get Brutes to a place where the team is happy with them".

343 plans to make coatings available through microtransactions as well as rewards for purchasing tie-in products such as Monster Energy drinks, Mondelez-branded snacks, and other items.

[105][106] 343 Industries' community manager John Junyszek defended the system, stating that it enabled "greater detail and variation" and that other methods of obtaining coatings would be made available as "special rewards" in addition to paid purchases.

[131][132][133] Additionally, GameSpot editor Jordan Ramée praised the game's new grappleshot feature and rewarding single-player progression system.

[120] PCMag complimented the soundtrack for providing "a mix of atmospheric exploration music, thrilling combat tracks, and songs and compositions that exist somewhere in between".

[125] PCGamesN praised the feel of each gun and engaging variety of the arsenal, saying "switching to the plasma rifle to knock the shield off a Jackal and then back to the VK78 Commando to get a snappy headshot never gets old".

[123] Rock Paper Shotgun liked the world design, but criticized the plot as being held back by prior entries, "Infinite's story is still ankle-clamped by the overindulgence of its predecessors, even though it does what it can to shrink things down into a tighter, more coherent spacetale".