Revealing mistake: Although the revelers in Dallas are celebrating the 4th of July, it's very obvious by the characters' clothing that the film was shot during cold weather.
Factual error: A meteorite strikes a dam, flooding downtown Kansas City. There are no dams on the Missouri River within hundreds of miles of that location. Also, the apparent position of the dam would require the river to be flowing backwards. And downtown Kansas City sits atop a bluff, the flood would have gone elsewhere and not hit there.
Continuity mistake: The downtown skyline keeps changing during the scenes where an asteroid segment is threatening Kansas City.