Although history has shown that success is forthcoming no matter what you do to Charles Dickens' classic tales, The Muppets' approach leaves nothing to chance, more or less sticking to Dickens' story and setting, presenting the three spooks in a vision of Victorian London where Cockernee characters are as thick on the ground as snow.
Yet while it regards the ethics involved with reverence, this never forgets that there's entertainment at stake, and so the poverty looks pictaresque and the ghosts aren't too scary . Which is where Jim Henson’s 20 years of making people laugh (here continued by his son Brian) with these puppets comes into its own, knowing exactly how to draw on the cartoon possibilities to present enough virtual asides to fill the screen and ensure at least one laugh every two minutes. Also, because audience awareness of the Muppet characters is greater than that of the book's cast, the script allows them to be themselves: Bob Cratchit is the mild mannered, faintly bumbling Kermit: miss Piggy in psycho mode is his wife; the jovial Mr. Fozziwig owns a rubber chicken factory and there's much made of the fact that, as narrator, The Great Gonzo isn't Charles Dickens.
The biggest contributor to the success though is Michael Caine, wisely underplaying it as a mean Scrooge who is later almost embarrassed by his own generosity. In fact, Caine's so right in the part, you can almost forgive his singing. Almost.
