Factual error: During the scene where everyone runs outside, the Statue of Liberty head crashes into the street. The head is scaled too small and its size can be compared to the people taking pictures. In real life the statue head is large enough for people to walk into (17' from chin to cranium).
Factual error: In the first scene where the Army attacks the monster, the first tank that rolls by is actually a British FV-433 Abbot self-propelled gun made during the Vietnam war years, not an M109 Paladin which most people believe. (Paladin has a longer gun barrel, and has rear turret overhang.) And a few seconds later we see, next to the M1 Abrams, what appears to be an MLRS system firing, but is actually some kind of truck with a multiple rocket launcher, much like the Russian BM21, not the U.S. tracked MLRS system or the M1097 Avenger (which I originally thought it was).