Many people who saw this movie took it to be a cheesy B grade (or C grade?) movie about a giant shark battling a giant crocodile is instead a subtle philosophical commentary of our social mores and prejudices.
You see, the shark represents the male ego. So when the shark is terrorising the navy, it actually represents how the male ego has crushed the feminism of our society, and how men have ruined the environment.
The croc does not represent women, however. It represents corporate greed. Like the crocodile walks over everything, crushing anything in its path. The movie is trying to subtly show how corporate greed is out of control, and how it is destroying our civilisation.
There is a scene where the shark eats a nuclear submarine (yes, you read that right). Since the shark represents men, the submarine represents, well, something Freud talked about a lot. Since this is a family safe review, I hope you'll understand. So the scene shows how the male psyche is in pain, as it has been sexually repressed.
I am surprised this movie did not get an Oscar for best movie best direction and best script. Just goes to show how shallow our society has become, where cheap entertainment gets all the awards, and movies with deep messages, like this one, are ignored.