The Horus Heresy: Betrayal at Calth is a turn-based tactical strategy game set in the Warhammer 40k universe. The player will take control of the Ultramarines as they confront enemies who are trying to destroy the Imperium. With the help of the Dark Ritual, the Legion goes underground to engage in a brutal fight. The war will take place between the fighters of the 31st Millennium Adeptus Astartes.
The game takes place on the planet Calth Magos Omnal Sark, where Sergeant Acastus leads a squad of Ultramarines in the defense of the Imperium against an aggressive faction of the Word Bearers. The campaign consists of 4 acts, where special squads of Terminators, Dreadnoughts, Cultists, Apothecary and the devastating Moritat Legion will take part. The campaign involves commanding Legionnaires, Veterans, and Sergeants as you fight the heretics of the Word Bearers using a variety of weapons: Bolters, Plasma Cannons, Flamethrowers, and Rocket Launchers, and more.
Missions are available for single battles against artificial intelligence and network maps for multiplayer play. The multiplayer mode allows you to choose the side of the Ultramarines or the Word Bearers to face off in standard deathmatches. All progress from a single player game can be transferred to multiplayer by forming an individual Legion. The matchmaking system is looking for players all over the world. The Horus Heresy: Betrayal at Calth allows you to play using virtual reality helmets.