Lincoln Flynn’s recent essay argues that No Country for Old Men’s primary aim is to analyse the thematically significant perspective of Sheriff Bell, but that the film’s tonal disparity limits its artistic success:
I don’t agree that the shift in tone is a shortcoming. NCFOM is a faithful adaptation of McCarthy’s novel, leaving the Coens’ cinematic choices to serve as their stamp. Significantly, the medium of film carries its own baggage: we enter the film with established expectations about the role and purpose of an everyman/cowboy, a darkly charismatic villain and a competent yet comic sheriff (per Fargo).
The first half of the film does little to challenge those tropes, but the second half’s tonal shift coincides with a full-bodied attack on these archetypes. The kineticism of the film’s violence drains away (and is often kept off-screen). Bell moves from comic relief to the thematic core of the film. Moss’s heroic defiance proves … insufficient.
The tonal shift forces the audience to reconsider their expectations and reaction to the first act, and, importantly, other films using those same tropes. Muting the violence throughout might suit NCFOM’s themes better, but would limit its ability to serve as a critique of cinema.