After the player finishes the campaign, Veteran Mode will be unlocked. It allows players to remix the campaign missions with different modifiers such as bonus damages and accuracy penalty. The game, however, does not have a multiplayer mode.
Story
One year after Emergence Day, when a subterranean race of creatures known as the Locust Horde emerged on the surface in a campaign to kill every human on the planet of Sera, Coalition of Ordered Governments leader, Chairman Richard Prescott, orders all major cities outside the Jacinto Plateau to be incinerated by the Hammer of Dawn.
In addition, the Chairman had sent mop-up detachments in key-cities to eradicate the surviving Locust. One of the mop-up crews was Alpha Squad, stationed in Aldair City. Among them is Pendulum Wars hero, Sgt. Gabriel Diaz, who had demoted himself to working in the motor pool.
Mere hours before the Hammer Strikes, he receives orders from Chairman Prescott and Major Sid Redburn to retrieve classified intel files from the CIC building. Sgt. Diaz and Major Redburn find the files that reveals to be about a Locust scientist named Ukkon, who has been responsible for the various creatures the Locust have been using as instruments of war.
The Hammer of Dawn then destroys the city of Aldair, but Sgt. Diaz and Major Redburn survive. However, Ukkon destroyed the army base and killed everyone. Prescott then orders Diaz to assassinate Ukkon and is granted the rights to do so by any means possible. In need of soldiers for the fight, Sgt. Diaz and Major Redburn rescue another mop-up squad, Echo-Five, but discover that Ukkon has been killing the mop-up crews.
After rescuing a Stranded group, a militia of civilians who survived the Hammer Strikes, they also join Alpha Squad. Their leader, Mikayla Dorn, is aware of Ukkon and escorts Sgt. Diaz and Major Redburn to the city of Claybourne where Ukkon frequents.
Upon spotting Ukkon, Mikayla manages to shoot Ukkon in the mouth and apparently kill him. Ukkon, however, comes back to life and immediately repairs the damages done to his face. Sgt. Diaz then realizes that the COG is once again holding secrets like before, and fears that they will get them killed.
With Ukkon a bigger threat then they thought, Sgt. Diaz then relocated his entire squad into the deserts of Vasgar to teach them how to fight and prepare for the battle against Ukkon. Eventually, Alpha discovers an empty canister that Ukkon had used to inhale earlier. Mikayla translates the canister as belonging to the Nedroma Health Institute.
Upon arriving, Mikayla reveals that Nedroma was a quarantine zone and research facility for Rustlung, a fatal condition caused by the exposure of Imulsion fumes. Upon finding Ukkon's stash of canisters, Mikayla reveals that the canisters are full of immune system boosters, but only work against Rustlung, and with devastating side-effects.
Realizing Ukkon is dying of Rustlung and in need of the canisters, Sgt. Diaz prepares a trap to lure Ukkon using the immune canisters as bait. Alpha Squad is successful in luring Ukkon and capturing him. However, Ukkon reveals to recognize Major Redburn as an old acquaintance.
Major Redburn then knocks out Sgt. Diaz and prepares to drive off with Ukkon, alive and imprisoned, back to Ephyra. Mikayla stops him, and Ukkon manages to break free and escape. Sgt. Diaz and Mikayla then detain Major Redburn, with Chairman Prescott ordering to execute him for treason.
Major Redburn then reveals to them that when he was younger, he worked for a genetics lab called the New Hope Research Facility, who, like Nedroma, was trying to cure Rustlung.
However, the scientists went mad and used genetic experimentation to try and evolve the patients into greater beings, but instead made monsters: the Locust. Most of the patients lost their minds and went feral, except for Ukkon. Ukkon had also developed the ability to quickly heal to the point of immortality.
When Chairman Prescott discovers that Alpha Squad had learned the truth about New Hope and the COG creating the Locust, he attempts to kill them with the Hammer of Dawn.
While Alpha were no longer part of the COG, they still believed in killing Ukkon. Major Redburn also revealed that the scientists at New Hope had created a fail-safe called cytostatic gas that could block Ukkon's healing ability, as Major Redburn believes he can make and weaponize it.
