While it is based on the same H.G. Wells book as yesterday's Island of Lost Souls, this movie is quite different. And not in a good way.
The film's director Richard Stanley had developed a script for this film for 4 years and was removed from the project less than a week into shooting. A reason was never given, but it is probable that he was unable to rein in star Val Kilmer, which lead to his firing. John Frankenheimer was brought in to salvage the film, and, I guess he did what he could. Frankenheimer also had major problems with Kilmer and famously is quoted as saying "There are two things I will never ever do in my whole life. The first is that I will never climb Mt. Everest. The second is that I will never work with Val Kilmer ever again." This movie is a mess.