Sam Rockwell is the agent of chaos as Marty's pal and wannabe actor Billy Bickle (an oblique reference to Taxi Driver?) who kidnaps a dog to claim the reward, unaware that the pooch belongs to Charlie.
Inspiration arrives like spurts of blood once Marty starts hanging around less with his girlfriend Kaya (a wasted Abbie Cornish) and more with his best friend Billy Bickle (Sam Rockwell), who, like his Travis Bickle namesake in Taxi Driver, has several screws loose.
At one point, Billy even does a quick “You talkin’ to me?”-type Taxi Driver riff.
Marty's best friend is Billy Bickle ( Sam Rockwell ), and if his last name is the same as the hero in Marty Scorsese's " Taxi Driver ," I leave that for you to puzzle out.
The picture is smart enough to work on multiple levels: as a witty salute to masculine '70s cinema ("Marty" can stand for Marty Scorsese as well as Martin McDonagh), as a deconstruction of same (Rockwell's "Bickle," alluding to De Niro's psychopath in Scorsese's Taxi Driver, symbolically embodies the eager violence Marty needs for a commercially successful script), and as an existential consideration of the role of self-expression in ascribing meaning to life, including the question of artistic "responsibility."