1. The immediate Hitchcock touch I noticed was his use of reaction. Like "Rear Window" especially, he shows the action unfolding then cuts to the reaction of the audience in this case.
2. I agree that Hitchcock's themes appear here but at the utmost infancy. The theme of voyeurism comes through as well as the object of affection being a blonde woman.
3. Hitchcock was never a big fan of sound if I recall correctly. He always preferred that the images drove the story and the themes. Many filmmakers of the era felt that silent films were at their purest without sound.