Battles are won either by holding a certain number of control points for a period of time or by destroying all of the opposing armies' HQ structures.

The game is set in the Warhammer 40,000 universe: a dystopian vision of the far future in which humanity has forged a galaxy-spanning empire, The Imperium of Man.

The Imperium, desperately fighting to preserve the human race from extinction, is in a state of constant war with alien species like the Orks or Eldar, as well as insurrections from renegade worlds or the human servants of Chaos, who employ demonic forces and sorcery under either of the Chaos Gods they serve, having deliberately betrayed their once godlike Emperor of Man.

The single player campaign is set on the planet Tartarus, an Imperial colony under siege by Ork invaders, with the player taking the role of the Space Marines' Blood Ravens 3rd Company, led by Captain Gabriel Angelos, that arrives to assist the planet's 37th Tartarus Planetary Defence Force Regiment of the Imperial Guard, led by Colonel Carus Brom.

The Blood Ravens' Space Marines, upon descent to the planet's surface, secure Tartarus' spaceport and start their own operations against the warring Orkish forces.

Angelos allows Toth use of Space Marine transports to assist in the evacuation but desires to remain and investigate, clashing with Toth's resolution, who cites that Angelos' previous request of an Exterminatus (a space-based planetary bombardment) on his once homeworld of Cyrene, years ago, may have affected his judgement, "seeing Chaos where it doesn't exist".

The Librarian, however, secretly harbours Chaos artifacts and he damages the Blood Ravens' transports to allow further research time, being influenced constantly by Sindri's temptations.

Angelos' forces track the Eldar to the urban settlement of Loovre Marr, engaging them in full-scale battle, as Sindri and the Alpha Legion infiltrate the city and abscond with an artifact, which Macha believes is the "key to the undoing of this world".

Toth explains that the Eldar presence on Tartarus was to prevent the Alpha Legion from unearthing the stone, unwilling to inform or cooperate with Imperial forces due to arrogant behaviour, seeing themselves as "the only capable defence against its influence".

Angelos and Toth make amends and advance against the primary position of the Alpha Legion, as it is performing an unholy ritual to unearth the Maledictum.

As all parties start to evacuate, Angelos is called back and faces the daemon that he has unknowingly freed from its prison, the Maledictum.

However, these weaknesses were considered to be minor, IGN summarised: "Nothing about the gameplay will really surprise anyone (though the addition of reinforceable squads is pretty neat) but it doesn't particularly matter ...

[21] German reviewer Daniel Matschijewsky awarded the game 83 out of 100, praising the user interface and the sound, but identifying the campaign and the AI as weaker areas.

[23] It received a runner-up position in GameSpot's 2004 "Best Strategy Game" award category across all platforms, losing to Rome: Total War.