A great movie!
And Lon Chaney is brilliant once again. TCM does a great job of bringing these movies and fortunately they show this one once in a while so you need to be on the lookout for it if you haven't seen it. I am not sure if any parts have been left off but TCM is pretty good at giving a verbal explanation of missing parts like they did with Metropolis.
SPOILIER WARNING! PLEASE READ NO FARTHER IF YOU HAVEN'T SEEN THIS MOVIE.
Lon Chaney is brilliant. You can never forget his fiendest joy as he tells Lionel about what he has done to his daughter but when Lionel laughs and tells him that it is really his (Lon's) daughter the expression of changing from cruel fiendest joy to extreme horror is priceless. A great movie indeed.