Warhammer 40,000: Space Marine

The events of the story take place on Forge World Graia, a planet devoted to producing military weapons for the Imperium of Man which has been invaded by alien Orks.

The game follows a Command Squad of three Ultramarines, a group of genetically-engineered, cybernetically enhanced super soldiers referred to in-universe as "Space Marines" or "Adeptus Astartes". The main characters are 2nd Company Commander and playable character Captain Titus (voiced by Mark Strong), his immediate subordinate Veteran Sergeant Sidonus, and a relatively inexperienced and by-the-book Tactical Marine named Leandros. Other notable characters include Imperial Guard commander Second Lieutenant Miranda 'Mira' Nero and Ordo Xenos Inquisitor Drogan.

After the invasion of Forge World Graia by Orks, Imperial military commanders consider various methods to regain control of Graia, especially since the loss of Graia's industrial output has greatly affected local Imperial war-making capabilities. In the end, it is decided to deploy a group of Space Marines of the Ultramarines chapter to reinforce local Imperial forces.

Initially upon arrival, the squad provides assistance to the outnumbered and overrun Imperial Guard regiments fighting on the planet's surface, which after the loss in battle of all higher-ranking officers are now being led by the sole surviving junior officer, Second Lieutenant Miranda 'Mira' Nero; she informs Titus of the present situation and briefly accompanies the squad to their next engagement. Titus agrees to silence the captured planetary defense cannon, which has been preventing supply ships from reaching the beleaguered defenders. This done, Mira thanks the Space Marines and continues to help Titus however she can over the course of the game, amidst re-organizing the remaining Imperial Guard forces and attempting to hold the majority of the invading hordes at bay until the delayed reinforcement fleet arrives. The Space Marines then move on to continue with their own mission and, amidst securing the Titan Invictus (one of a class of giant, bipedal war machines that are produced primarily on Graia and the principal reason for the Ultramarines' deployment there), answer a distress call from the injured Imperial Inquisitor Drogan, from whom they learn of a weapon that can wipe out the Orks, but which needs a power source that is located in a reactor below the Manufactorum. Titus retrieves it and activates the Psychic Scourge, but the Orks are not killed. Instead, a Warp gate to the psychic realm of Chaos is opened, unleashing several daemons that massacre the surrounding Orks. Moments later, the Chaos Lord Nemeroth emerges from the portal. Using his Warp powers, he subdues the Space Marine squad as Inquisitor Drogan arrives via lift and approaches Nemeroth, revealing his allegiance to the Chaos Lord. It is then revealed that Drogan was killed at some point prior to meeting Titus and his corpse was possessed and used by Nemeroth as a sleeper agent. Titus gathers enough strength to grab the Power Source, which had been ejected from the Scourge, and Nemeroth is ambushed by Grimskull, the Ork Warboss in charge of their invasion of Graia, allowing the Space Marines to escape.

The Scourge opens a growing Warp portal around the Orbital Spire, allowing Chaos forces to pour in; seeing this, Titus forms a plan to destroy the portal and the Spire by using one of the Titans they had secured earlier (their original mission). On the way, Titus faces Grimskull again and finally ends his life with a plasma shot to the head after a grueling battle. The Titan Invictus is supercharged by the Power Source and destroys the Spire. Realizing that the Power Source is too dangerous to be entrusted by anyone, even the Inquisition, Titus decides to bring it back to the Chapter Master of The Ultramarine and the Chief Librarian so they can seal it in the Chapter’s armory. However, Sidonus is killed by Nemeroth, the Power Source is stolen and taken to the floating remains of the Spire.

The reinforcement fleet now having finally arrived, including a company of Blood Ravens Space Marines, the rest of Titus's company and large numbers of Imperial Guard, Titus leads them in an attack through the remaining Chaos forces to stop Nemeroth from performing a ritual to ascend to the status of a Daemon Prince using the power of the device. Nemeroth has partially ascended to Daemonhood when Titus finally faces him again; both are knocked off the spire in the struggle, and the Captain defeats him in single combat while falling towards the ground. He then breaks the experimental device in half with his hands. Titus survives the exposure to the raw Warp energy again, and is rescued by a Thunderhawk dropship before he can impact the ground.

The end scene of the game involves a new Imperial Inquisitor by the name of Thrax, accompanied by Leandros and escorted by several Black Templar Space Marines, who places Titus under arrest. Leandros believes that his Captain has been corrupted by Chaos based on Titus’ resistance to warp energies. Titus denies accusations of heresy and is backed up in this by Lieutenant Mira who also protests the accusation, but Titus warns her to back down, knowing the extent of the Inquisition's wrath. Titus is willing to find the cause of his own mysterious resistance to Chaos, and voluntarily goes with Inquisitor Thrax on the condition that the Inquisition leaves the planet, its inhabitants (including Mira) and his fellow Ultramarines alone. Before taking off from the planet, Titus chastises Leandros for his singleminded following of the Codex Astartes, and his inability to see past it and think for himself - something Titus believes is the true test of a Space Marine.

A computerised report in Imperial records shows that the threat on Graia has been contained. The planet is under quarantine by order of Inquisitor Thrax, and Titus is under investigation by the Inquisition on charges of heresy.

Several character skins and models for Space Marine and Chaos Marine chapters have been released, along with content that was originally reserved for those who preordered the game. A new wave based game mode called "Exterminatus" was also made available for free download.

A downloadable content (DLC) package titled "Chaos Unleashed" was released on December 20, 2011. It adds a new mode to Exterminatus where players can take on the role of Chaos Space Marines as they fight both the Ork horde and Imperial Guard forces. The pack also includes three new multiplayer maps: Habs Ablaze, Station Tertius, and Aquila Canyon, which can be played in all multiplayer game modes, and ten new achievements and trophies.

An additional DLC package, "The Dreadnought", was released on January 24, 2012. This premium add-on added a new multiplayer mode called "Dreadnought Assault", in which two teams battle to capture a central location on the map and the winners spawn a player-controlled Dreadnought. The Dreadnought is armed with an Assault Cannon / Autocannon, a Meltagun and a Power Fist / Power Claw and the team must capture points across the map to score points. The Dreadnought DLC also includes three new multiplayer maps: Desolation, Dome Mechanicus, and Chem Refinery.

The soundtrack for Warhammer 40,000: Space Marine was composed by Cris Velasco and Sascha Dikiciyan.[1]