This is going to be a bit of a book review and a movie review. Why? Because I recently finished the novel I Am Legend, which is the inspiration for this film and even has the same writer.
Last Man on Earth is a movie about Vincent Price fighting off hordes of the undead in and effort to survive.
I don't understand Matheson's complaints with this movie. It's better than the film featuring Will Smith and follows the narrative much more closely. One of the complaints I had with the book is Robert Neville being a layman at the start of the book and by the end he's become like a molecular biologist. Last Man on Earth instead opts to make Neville (here called Morgan) a doctor before the vampire outbreak.
The film also immediately addresses Morgan being immune due to a bite from a vampire bat in Panama instead of waiting until the end like the book did. Despite the major differences, I really enjoy Last Man on Earth and the way it handles a vampire apocalypse.
Many will compare it to something like Night of the Living Dead due to the similar plot and tone of the overall film, but Last Man on Earth was made first.
While it is based on a book and may be a premise that has been done to death in recent years, I feel that Last Man on Earth is still an enjoyable film in its own right. Plus, Vincent Price is just a ton of fun to watch in anything.