Revealing mistake: When the Japanese tanks are firing upon Godzilla, one of the pyro effects catches the Godzilla suit on fire (at the arm). One can see the stunt man begin to frantically shake his arm upon this realization before the editing cuts to another shot.
Other mistake: The guy says "looks like I'll have to send more flowers" then opens up the activation card and code to destroy the building. The code is 50617 but he swipes the card then pushes 50671. (01:00:00)
Suggested correction: If you watch the keys again he presses the exact appropriate numbers in order. 50617.
Other mistake: Although this is set in Tokyo, Japan, the Army general is wearing a U.S. Airborne Jump Wings patch.