I Am Legend was a disappointing movie. Most of the people I have spoken to said that it felt like half a film.
The ending was a particulaly huge let down. It completely missed the point of the book and rendered the title absolutely redundant.
The big sticking point is that there is another ending – a much better, more appropriate ending – that the US test audiences either didn’t like or couldn’t get their heads around. It actually makes more sense than the final ending and it would not have caused me to launch myself at the screen yelling: “Why the hell have you ruined another perfectly good movie with a stupid Hollywood ‘happy ending’?”
Thankfully, one kind person has leaked it to the internet and it’s everywhere to be seen. You can see it here if you want. I thoroughly recommend watching it. It will have you questioning the sensibilities of American test audiences.