A comedy as black as vinyl, “Kill Your Friends” is a music-industry tell-all set at a decadent London record label in 1997.

Nicholas Hoult (once the boy in “About a Boy” and lately one of the X-Men), plays a degenerate A&R man (talent finder) who, desperate for a hit record, finds himself splattering a friend’s brains all over the floor after a job setback.

Hoult needs the gonzo charisma of Ewan McGregor in “Trainspotting” or Christian Bale in “American Psycho” to pull this off, and he doesn’t. Though the script is full of arch, darkly funny observations, the movie gets stuck on the same clanging chord of all-hating cynicism. A third act that raps things up far too tidily doesn’t help matters much.