One of the most distinctive features of "Blackmail" is its use of subtitles. As the film begins, Hitchcock employs intertitles to convey the characters' dialogue, a common practice in silent films. However, as the story progresses, the subtitles become more sparse, replaced by synchronized sound effects and music. This gradual shift from visual to aural storytelling enables Hitchcock to build tension and suspense, drawing the audience into the world of the film.