Sisters is a 1973 horror thriller directed by Brian De Palma. Margot Kidder stars as a heavily accented version of French Canadian separated conjoined twins. Wow... Charles Durning also stars. Reviewers seem to like it. I found Kidder's accent annoying and hard to get past. Once I was able to get past it, though, I found this an effective thriller and an interesting mystery.
Slant Magazine gives it 3 1/2 out of 4 stars. 1000 Misspent Hours closes with this: "the last half-hour or so is the phase in which Sisters finally shows its teeth, and although there is humor even then, it serves to emphasize the horror of the proceedings rather than to lessen it. It also reveals De Palma as a much more agile filmmaker than he is often credited with being." HorrorNews.net says, "his [De Palma's] most Hitchcockian film, Sisters (1973), remains his most original." Roger Ebert calls it "a neat little mystery picture". Rotten Tomatoes has a critics score of 83%.