The first-person perspective could be viewed as a brave experiment or a case-study of why nobody EVER makes movies this way. Three points:

1) In a movie, we like to see the main character reacting.

2) Actors look self-conscious when endlessly talking to a camera.

3) The lack of edits makes many scenes tedious.

Still, you can admire how hard all this was to stage and shoot, in a age when cameras weighed a ton, made too much noise and nobody owned a Steadicam. Reminds me of the kind of crazy gimmicks Hitchcock sometimes tried but Hitch would have never let the train go this far off the tracks.