My reaction to 'The Moon-Spinners' is mixed, but I believe it’s enjoyable enough overall. I appreciate the initial concept, however, I wasn't pleased with how the film presented it; certain characters seem to appear abruptly and then become significant without much explanation. I do acknowledge the visual aspects of the movie – it was filmed beautifully in some lovely Greek settings. The pacing felt uneven though; a shorter, more brisk runtime would have improved the plot’s delivery. Hayley Mills, appearing in what would be her second-to-last Disney film, is certainly a talented actress, but her portrayal of Nikky isn't very effective – largely because of the writing, particularly early on when Nikky and Frances (Joan Greenwood) come across as rather unpleasant; I don’t believe that was deliberate. Eli Wallach (Stratos) and Peter McEnery (Mark) deliver the strongest performances, which is likely why I found myself somewhat entertained, as their characters are consistently connected throughout the story. The cast is adequate, but the storytelling itself wasn't particularly well handled. There are some genuinely interesting parts alongside disappointing ones, ultimately bringing it to a point where it could probably be considered decent.

Source on TMDB