There's a lot of Agatha Christie that hasn't been filmed, and it's probably too late now for most of it. Her massive output is rarely great but always decent, if not good, explaining why she does well on the small screen but often not on the large.
In Agatha Christie murder is an entertainment, and always tame. A scream and a shot, or very often something nastier; but never any blood. If the eight or nine murders in Ten Little Indians were to be graphically filmed, or realistically portrayed, we'd be watching a shocking and painful horror film, as upsetting as any of the Saw films. As it is, murder in a typical Agatha Production is quite quick and clean and natural, no matter what the method.
Mario Adorf is at home in this, though that isn't a compliment, given that it is so light as to be almost farcical; at least it suited him in 1965 when Ten Little Indians was released; and he looks pretty silly. He obviously grew in power and stature as age came upon him. Here though, he is quite the part of the petulant servant. In the credits he is listed last; I think his face reflects his disappointment with this.
There are some excellent cast members in Ten Little Indians; Stanley Holloway, Shirley Eaton, Dennis Price to begin with. It will take a while to get over this cast, as a mater of fact; Shirley Eaton who one year before had played Jill Masterson in Goldfinger (1964) and been painted in head to foot in gold paint; hers is a tremendous performance here, though I've sometimes wondered about how she felt about the way she was rendered in the film poster; buxom and insane, neither of which she is.
It's not often either that you get to see swinging teen idol Fabiano Anthony Forte, better known to his fans as Fabian, in a movie; though he has made plenty. Heavyweight stars include Wilfrid Hyde-White (1903–1991); Dennis Price (see Victim 1961); and Stanley Holloway who is too many good things to mention. Israeli beauty Daliah Lavi also does well here; one of her first English speaking parts and others that followed included Casino Royale and grand 1960s curiosity OK Connery (1967), starring Neil Connery and many Bond cameos including Bernard Lee, Lois Maxwell, Daniela Bianchi (From Russia with Love), Anthony Dawson (Dr No) and Adolfo Celi (Thunderball himself). The movie's taglines 'Neil Connery' is too much' and 'OPERATION KID BROTHER is Too Much for One Mother!' are parodies of the tagline for the James Bond spoof movie Casino Royale which says "Casino Royale is too much for one James Bond!".
For Mario Adorf, this was the year of the big launch, and the same year he appeared in Major Dundee, his two English speaking roles to date. He is quite funny in Ten Little Indians, but not that convincing, and he has a fairly drawn out fight scene with Hugh O'Brien that seems out of character; but what is his character?
Watching Ten Little Indians you feel that Mario Adorf has been hired for his squashed up and silly face, with its silly moustache. There isn't much of the way in charcater that shines through and yet he has something that you feel is going to have him endlessly typecast, which he was at least until 1971, when he ended up playing Brother Tuck in an Italian, L'arciere di Sherwood, which by all accounts is fairly funny, and a quite zippy Spaghetti Robin Hood.