In Titanfall, players control "Pilots" and their mech-style Titans, and fight in six-on-six matches set in the war-torn outer space colonies of the Frontier.

[11] There are three unique Titan classes, variants of light, medium, and heavy, with inversely related speed and armor:[13] the all-rounder Atlas, the bulky Ogre, and the fleet-footed Stryder.

Leading their mercenary forces are Frontier operations commander-in-chief Vice Admiral Marcus Graves, intel specialist Sergeant Kuben Blisk, and artificial intelligence companion Spyglass who handles Titan deployment.

In addition to the obvious combat applications, unarmed forms of Titans are used in heavy industries like cargo transport and deep space ship salvage.

Increasing demand for Titan manufacturing materials, combined with Hammond's market-cornering planetary survey technology and map database rights, contributed to explosive growth for the company.

With the Frontier's valuable shipping lanes and vast planetary resources ripe for exploitation, the IMC is dedicated to maximizing profits and shareholder wealth, using the legal application of force when necessary.

Following the death of General Anderson, forces of the 1st Militia Fleet led by Cheng "Bish" Lorck and Sarah Briggs conduct a raid on an IMC fueling facility in an effort to refuel their ships while IMC forces led by Vice Admiral Marcus Graves attempt to stop them by setting up defensive turrets to wipe out the Militia's ships.

When he learns that his former commanding officer Graves is involved in the colony's destruction, he contacts the Militia and offers to help them beat the IMC in exchange for evacuating the remaining survivors at the wreckage of the IMS Odessey.

The Militia makes contact with MacAllan at the Odessey and helps him buy time to allow his people to escape while he attempts to extract data from the ship's computers.

Although Graves attempts to have the Sentinel repaired at Outpost 207, a surprise attack led by Sarah puts the ship out of action to slow the IMC down.

With masses of human combatants having defected from the IMC to the Militia, the newly promoted Vice Admiral Spyglass and Commander Blisk coordinate the factory's defense.

Following the battle, Spyglass makes an announcement that although the IMC is on the defensive they are still a force to be reckoned with while the Militia plays an inspirational message recorded by MacAllan before his death stating that they will fight for independence across the Frontier.

Following Call of Duty: Modern Warfare 2's release, Activision fired Infinity Ward co-founders Jason West and Vince Zampella in March 2010 for "breaches of contract and insubordination".

[26][27] Later that year, West and Zampella founded a game development company, Respawn Entertainment,[25] composed largely of the former Infinity Ward staff—those responsible for the successful Call of Duty series.

[28] Project influences include Blade Runner, Star Wars, Abrams Battle Tank,[31] and Masamune Shirow of Ghost in the Shell.

[40] Electronic Arts CFO Blake Jorgensen later added that the Microsoft exclusivity agreement would last "for the life of the title", such that other consoles, including the PlayStation 4, will not receive a Titanfall port.

[30] The 65-person[30] development team experimented with different gameplay before consolidating to three goals: "player mobility, survivability, and the merging of cinematic design with fast-paced action".

[44] They identified contemporary first-person shooters as restricted to "a single plane of movement", the cardinal directions and hiding in place, and considered new features to increase mobility, such as a three-story-high jump.

[44] The parkour mechanics came from a similar, basic wall running mod made by a Respawn programmer for Half-Life 2 when testing potential game engines.

[19] Producer Drew McCoy wrote that the non-human artificial intelligence (AI) players were not bots meant to replace humans, but "a different class of character in the game".

[19] The AI players were designed to enliven the battlefield environment with a greater sense of scale and drama, and to increase the game's complexity with new opportunities for strategy and cannon fodder for Titans.

[30] Respawn chose to build Titanfall on the Source game engine early in their production cycle due to their developers' familiarity and its ability to maintain 60 frames per second on both the Xbox 360 and PlayStation 3.

[30] In an interview, Respawn software engineer Richard Baker said the company chose Source since Portal 2 performed well on the PlayStation 3 with it, and the console was "the riskiest platform in seventh generation".

[65] The game's South African release was cancelled due to poor connectivity performance during the beta and no nearby Microsoft Azure data center in the region.

[95] Reporting for Polygon at E3, Arthur Gies praised the "dynamism" between the Titan's brute force and the pilots' objective-based stealth as the game's greatest asset.

[20][12][109][110] Reviewers complained that the AI grunts were too unintelligent,[14][8] that private match and community support features were lacking,[20][14][8][110] and that the game had shipped with too few multiplayer modes.

[14][29][112] Edge noted that the parkour elements made them approach at an angle instead of rushing directly at the dots on the mini-map,[14] and GameSpot's Chris Watters said simple player movement was both a pleasure and a challenge.

[114] Writing for The Verge, Adi Robertson compared the plot to the backstory on 1990s CD-ROM user manuals,[113] and OXM's Mikel Reparaz felt his actions were unimportant to the narrative.

[12] Peter Bright of Ars Technica wrote that the game's multiplayer was "not groundbreaking" and did not surpass Call of Duty's,[110] and Edge decided that Titanfall "might not be Xbox One's killer app".

Jaz Rignall of USgamer revisited Titanfall in late 2015 and found the game still worthy of its original praise, though he noted that its technical details—namely graphics and framerate—showed some age.