The single player campaign is structured as a series of nine missions, each set in a large maze representing a sub-vessel aboard the game’s mega-hulk (sometimes a bunch of ships get mashed together in the warp). You take the role of a chapter Librarian and fight alongside two AI squadmates that take basic move, guard and heal orders, but otherwise fight automatically. As you move between waypoints hordes of Tyranids erupt from floor-vents and unseen nests in the cabled awnings above. In addition to the melee-focused warrior variants, Tyranid/human hybrids can gun you down from range—at great speed if they have a couple of rocket launchers.
The addition of skill trees for your librarian adds some light RPG progression, and his psychic abilities (particularly the lightning strike) are fun to use. The real variation comes from weapon pickups, though. Lighting claws or the mace-and-shield combo feel significantly different to the pray-and-spray minigun and the shotgun-esque storm bolter. Melee attacks feel flailing and imprecise, particularly compared to the mighty hammers and blades of the Warhammer fantasy first-person squad game, Vermintide. The rapid-fire guns are better, but the process of fending off Tyranids, and even the hulks themselves, becomes wearying after a few hours. The story, sustained by visions mystic visions and comms chat from your superiors, doesn’t help. There are interesting hooks for 40K fans, but to newcomers it’s largely gibberish concerning the lost secrets of the Dark Angels chapter.