I disagree with the negative comments here. The movie held my attention throughout and was a delight to watch. Faye Dunaway’s portrayal of the dual roles was over the top but that was the nature of the two women she played. The actress Jane Wilkinson is clearly based on some of the mannerisms of Marilyn Monroe and Faye does this convincingly.
I didn’t initially think Peter Ustinov would make a good Poirot, but he captures the detective’s droll and determined persona and is quite convincing.
I wish they would make more movies like this. Though Peter and Faye are clearly the lead actors in it, there’s an ensemble cast that works together to lead us on a merry chase of suspects. The locations are magnificent. All in all this is definitely worth watching even if it lacks the big budget of the ones Ustinov made for theatrical release.