Audio problem: Just before midnight when the band is playing "Morning After" the camera pans out for a wide shot of the dance floor - the dancers are dancing MUCH too fast for such a slow song - and you do still hear the song.
Visible crew/equipment: When Rev. Scott swims up the first stairwell, after pushing aside the dead crew member, as his head comes up the shaft, you can see, very quickly, the flippers of a crewmember swimming out of the shot behind him.
Factual error: Throughout the end there is fire everywhere. All of that fire would consume any oxygen that was in the rooms and fill the rooms with heavy black smoke. They are walking and climbing everywhere without the effects that the smoke and lack of oxygen would have caused.
Trivia: The look of the set for the upside down engine room was so real, the actors refused to climb anything, fearing that it would fall. The set designer and builders had to climb it first to prove it would hold.