Two points stood out to me in regard to seeing the "future" Hitchcock in this early clip.
First was the use of the out-of-focus view through the opera glasses that eventually focus on the legs of the women dancing. I'm reminded of two scenes in his later films. I recall in Rear Window the initial view of Grace Kelly's face as she moves closer to Jimmy Stewart as he awakens from his nap. We know who she probably is but we see his perspective as he awakens and his view focuses on her face coming close to his for a kiss. The other scene is that remarkable moment in Vertigo as Kim Novak emerges from the bathroom in her hotel room dressed in the "Madelyn" clothing and hairstyle, something he coaxed her into doing. She emerges from the cloud of soft neon light from the hotel's sign outside the window, coming into his view slowly, as the mood of the scene compresses both their passions for one another.
The second was the scene at the theater entrance, as the to thieves watch the young woman fretting about entering the entrance for an introduction. The looks on the faces of men are obvious; they're up to no good. We know, as Hitchcock cuts to the shot of her handbag, that their idea is to steal something from it. The viewer, as someone previously commented, wants to yell out to warn her because we know she's going to be a victim of the pickpocket. I'm reminded of Hitchcock once describing how he wanted to show the audience, in the example he used, that there was danger in the scene, such as a bomb under a table. The viewer knows it's there, but the characters don't and the tension comes in waiting for the explosion, as opposed to both the audience and the characters suddenly surprised by that happening.
