Definitely as impactful as its reputation. It’s very dark, and shot on real locations, however, I can’t say that I’m astonished by the “realism” of the photography. There are several films before this one that look just as "realistic" as this, Ossessione again being one of them.
This film is powerful for portraying Nazism as raw as it did and at the time that it did. The only other presentations of Nazis were through highly propagandistic war films or satires in a way. There wasn't really a true historically realist depiction of them at least narratively to this degree as in this film. So this film in a way is poking into a bleeding wound and stirring up raw feelings literally at the close of the war.
In that vein, we see how stories are becoming more powerful during and after WW2. The war shifted the moral code of the universe so drastically, that there are no happy endings, the characters are criminals as well and the notion of right and wrong is distorted so that there is no clear answer. This film dives into that moralistic no mans land very well and clearly.
This film is the first major work of Italian NeoRealism without giving credit to Ossessione although as I noted above this film was not the first to initiate this revolution, there are several American films that also push the genre in this way, as well as British war films.
I will give Rosellini credit for making a film using all natural lighting. The movie makes great use of its natural sets and lighting conditions although there are a few scenes in the apartments or even courtyards that feel a bit "dark".
However, the documentary style in this film is not that. It's clear he didn't film this in a free flowing documentary style atmosphere where he collected real people, locations and props and just sent them into a scene and shot it with light gear and whatever was available. The shots in this film are highly composed and highly staged and the action is very well choreographed with lighting really emphasizing the scene. I think historians overplay the role this film had in shaping the whole docu-style Italian Neo-realist movement. Honestly this film comes across far more as a low budget Hollywood film more than it does a foreign indie "realist" film. There's lots of shallow depth of field portrait style close ups and clearly staged and set up interrogation shots that do smack more of a Hollywood film of the day than a European indie.
The shot that's most notable to me in representing this dramatic storytelling through camerawork rather than documentaryesque observational camerawork is when the truck drives away with the woman's son and she runs after it and is shot in the street. The camera pulls back with the truck looking at her. That's a makeshift dolly of sorts to create a dramatic ending whereby the camera pulls back, a classic Hollywood convention.
Historians have noted that this film was a continuation of the realism of the 30’s, which I would say is true from Bunuel to Visconti to even Jean Vigo and the British film, Fires Were Started, yes this movie pushed things forward, but I would argue it was not intentional in the sense of DOGME 95, which was a stylistic decision to intentionally limit your production to the barest of resources rather than just lacking the budget to do the movie right which seems to be the case for this film. Rosellini's later movies are all shot in a classic Hollywood style with tracking shots, shallow depth of field close ups, lots of lighting, big name actors, etc... That pattern to me suggests he just didn't have a lot of money for this film so he used things such as real actors, locations and natural light at times to get what he needed rather than because he wanted the film to appear "realistic." The shots are locked, very rarely are they done in the handheld documentary style, there are close ups intercut with wide shots. This feels like a film made by filmmakers, with intent, rather than a filmmaker trying to portray life as realistically as possible.