- Where did the snare trap come from that catches Robert Neville? This is never adequately explained.
- The manner in which Neville's wife and daughter die robs the movie of a dynamite and horrific conflict from the book.
- The "vampires" (the movie never calls them that) are ultimately much less interesting than Matheson's sinister, howling creatures. (Where is the chilling cry of "Come out, Neville, come out!"?)
- The vampires don't besiege Neville's home nightly. Apparently they just don't know where he lives. Another chance for suspense—gone.
- Neville fills up his day with meaningless tasks and bland research in his basement; he doesn't go out and try to systematically slay the sleeping vampires. Why on earth would you cut this?
- The ending. Come on, you've got one of the most awesome horror movie conclusions handed to you on a silver platter... but no, you've got to swipe the finale from a Chuck Heston movie.
- The Bob Marley speech. What is that about?
This upshot of all this? I never thought I would say it, but The Last Man on Earth, for all its clumsy budgetary limitations and "Italy pretending to be Los Angeles" weirdness, is still the best adaptation of I Am Legend. Chances of filmmakers getting a fourth shot at the book are pretty slim, unfortunately.