The dialogue is hard-bitten and Mamet-sharp.

The Iceman is a vivid evocation of a remorseless sociopath sustaining a double life as a contract killer and devoted family man. Gritty, gripping and unrelentingly intense, Ariel Vromen’s film boasts richly detailed character work from an ideal cast.

The point of The Iceman is “Even monsters are human,” but it takes a great actor to make a dubious theme convincing.

Ultimately, this is a grim (both visually and thematically) character study of an unsympathetic character, leaving Shannon, who manages to deliver another impressive performance, twisting in the ice-cold wind.

As a demonstration of the banality of evil, The Iceman is certainly effective and Shannon's performance gives the film its power.