As in the previous Bogliano's film -Sudor Frío-, Penumbra's Script is simply horrible. The movie is boring, and in the first 30 or 40 minutes, with the only exception of a flawless attack scene at the first minute of the movie, it seems more like a bad "artie" film in which nothing happens than a Horror/Thriller/Fantasy movie. During the entire movie the dialogs are extremely long (aaaaghhhhh, extreeeemelyyyy long!!!), expository, and unnatural. The attempt to keep mystery and reveal the plot essence gradually failed totally, obtaining a very unattractive and dull development of the events.
The acting of "Berta" Muñiz is awful and the one of Camila Bordonaba is poor too. Different is the case of Arnaldo Andre's performance, but his character is not exploited enough in the film. At this point is obvious that Bogliano believes acting is not important in Horror films.
Like in Sudor Frío, in Penumbra Bogliano underestimates and miss the erotic aspect, so appropriate at Horror Thrillers. Penumbra has a Plot linked with a Cult-like small group, the main characters are most of the time inside the same apartment, and above all it's an empty-plot bad- filmed silly movie, so some scenes of dark, nasty sex and erotic playing would have been absolutely suitable.
It's important to stress that (unlike the rest of Bogliano's works) Penumbra is not such a Horror movie, but more close to a tepid film about people settling a rent contract for an apartment.