During a scene where the boss of the TV station is talking to his staff, when he finishes he takes off his glasses and starts to move off his chair. Yet in the next shot he gets off the chair still wearing his glasses.
If you happen to have the DVD version of the film, have a look at one of the trailers. In the movie trailer they show the comet hitting the ocean at an almost right-angle. In the actual movie the comet enters the atmosphere at an angle, thus letting the people watch the comet travel to across the sky into the ocean.