Factual error: While hanging from the top of the Empire State Building, the sailor looks straight down the side of the building, which is shown to be flat. This is wrong. From the observation deck, there is another level that sticks out below, where the lights that shine upwards are stored.
Factual error: In the water tank sequence, Lamont takes a breath through one of the bullet holes. At more than five feet below the surface of water, the human diaphragm cannot push against the water pressure surrounding the chest, making it impossible to take a breath normally. Lamont should not have been able to draw breath at that depth.