Hitchcock's Blackmail exists in two versions, silent and sound. The studio producing Blackmail had Hitchcock shoot some of the scenes with sound, so this film is generally considered the first British sound film
The story is about the girlfriend of a Scotland Yard detective who has to cover up the murder of a man who was attempting to rape her. The story focuses on her attempts to keep from being blackmailed by a man who witnessed the crime. Considering the age of the film and the constraints Hitchcock had to deal with the film is reasonably watchable. When it came to making movies Alfred Hitchcock always knew where to place the camera in a scene and how to edit it for maximum impact even in an early film like this.
The running time is 85 minutes on the sound version that I watched.