From the website:
Pit the mighty Blood Angels Terminators against a lethal swarm of agile Genestealers in this two player board game. Inside the cramped confines of a derelict Space Hulk known as the Sin of Damnation, the Blood Angels must fight to save Mankind from the alien menace that lies within.
Games of Space Hulk are played on a gaming area made up of high-quality card tiles which fit together to create the cramped confines of the Space Hulk. Each of the 16 missions included in the boxed game uses a different set-up, or alternatively you can assemble the pieces in any way you like and create your own bespoke games.