This is a lovely sci-fi thriller. There is drama, comedy, and suspense, all that you could hope for in a summer flick. Mel Gibson does a wonderful acting job and his character certainly grows through the movie. Otherwise the other characters in the film are rather flat and the acting is not all that memorable. There is the cutest little girl I have ever seen in the movie. This is not a hard-core sci-fi flick and thus should just be taken as an interesting story and not much else.