It's environment is rendered in 3D, unlike its predecessor, Doom. Would he be interested in that sort of thing?
It offers full real-time 3D renderings which is very rare for games of that type and time period.
My husband likes video games - I've heard there is one called Quake - do you know much about it? I know that it's a first-person shooter from id Software and came out in 1996. Is there anything else you'd like to know? What could I tell my husband about it that would make him want to buy it? You could tell him that it's set in a medieval environment where you fight monsters with a bunch of different weapons. Monsters - oh that sounds right up his alley - what else?
Unlike the ''Doom'' engine before it, the ''Quake'' engine offered full real-time 3D rendering and had early support for 3D acceleration through OpenGL.