User Summary Fear the Alien, Burn the Heretic, Purge the Unclean. Warhammer 40,000 turn-based 4X (eXplore, eXpand, eXploit, eXterminate) strategy gameplay without diplomacy, this is Warhammer 40K, “In the grim darkness of the far future, there is only war.” Four playable factions with unique gameplay mechanics in the base game: Astra Militarum, Space Marines, Orks and Necrons. Chaos Space Marines and Tyranids have been added as purchasable DLC.