The reviews stating that this film is void of plot, acting, and merit are, for the most part, right on target. Cindy and Donna is nothing more than a soft-core exercise so prevalent in the 70s with a pseudo-story about two half-sisters sexually awakening - certainly peaking at different times as Donna is having a relationship - witnessed by Cindy - with Cindy's father(I think?). The material is spartan when it comes to plot development and really is just one sleazy scenario after another. There is essentially no acting in the movie except a rather mediocre performance coming from Susy Allen as the harried, booze-filled mother. Her performance was at least interesting if not definitely over-the-top. There is some weird moral the director and scriptwriter try to squeeze into all their soft-core nudity scenes, near-incest scenes, and masturbation scenes, but I wasn't buying. This film above all was a lesson in tedium and how one must sometimes endure even the most trying of films to get through to the end. Cindy and Donna is one of those films.