If given another shot, it sounds like Lawrence would've simply stuck to what worked in the text. Looking back, Francis Lawrence seems to think that audiences would've responded better to the film if it had stuck to the novella and told an arguably more straightforward siege story about a far more average man fighting an army of semi-intelligent vampires.

However, the film made a number of notable changes to the source material, not the least of which included changing the vampires to zombie-like monsters, and turning Neville into an expert scientist with a legitimate shot at curing the disease. I Am Legend was generally faithful to the source material in the sense that it focused its story on a character named Robert Neville (Will Smith) dealing with his status as the last man on Earth. We could have literally made the book, which I would have been much happier with, but you know when you're spending that much money you're panicking that you're making this weird little kind of art film about a guy alone with a dog in New York and you're trying to you know sort of create that spectacle. They would have accepted the nihilistic ending, they would have accepted vampires instead of people with infections. Looking back at it now, I think that we could have just done basically the story of the novella straight up and made the same amount of money in terms of ticket sales because people went I think for the last man on earth.

I am legend what are the monsters