Of course the acting is a little wooden but there are decent performances from Herbert Lom as "Captain Nemo", Joan Greenwood as "Lady Fairchild", and Gary Merrill (the former MR. Bette Davis) as "Mr. Spillet".
The real highlight for this viewer upon the film's release was the inclusion of a pivotal character portrayed by a black man, Dan Jackson as "Neb". The character is in the novel but he is younger and a bit too "subservient," reflecting the times of the book's publication. In 1961 it was notable to see a black man in a fantasy film, portraying an "equal" to his fellow castaways.
The DVD extras, including the documentary "The Harryhausen Chronicles", are adequate but the film holds its own as a wonderful excursion into the fanciful and makes for a fine family film.