Other mistake: When Alex Hopper is being tasered and arrested for robbing the convenience store, you can see his shirt is almost clean on his back. But he fell on the bottles and sodas rack in the store, the shirt should have stains.
Continuity mistake: In the scene on the mountain where the Hawaii police ask Mick and Sam to leave the mountain. Mick and Sam ask why and they are told during the conversation that the aliens have blocked all cell phones, radio and internet but in the next scene with the police they use a radio to communicate with each other.
Continuity mistake: At the scene when Hopper is playing soccer he receives a kick to his face, however the blood on his face changes between shots.
Continuity mistake: When Hopper climbs to the roof of the convenience store, the time displayed in the upper left corner of the screen (presumably a video surveillance camera) goes from 12:11.57 to 12:12.12, then back to 12:11.36.
Factual error: When the alien ship crashes into Hong Kong's Bank of China building, flaming debris can be seen flying past the statue of the Big Buddha, which was also established in an earlier shot as being located just behind the financial area of the city, Central. In reality, the Big Buddha is nowhere NEAR Central, out of view of the Peak, and not even located on Hong Kong island - but on Lantau island, to the west. The Big Buddha is also not included in the Hong Kong city skyline.
Other mistake: The shot of the fleet outside of the barrier is reversed. The Aircraft carriers landing deck is slanted right instead of left.
Other mistake: Alex Hopper's brother receives posthumously a Navy Cross (2nd highest award) for attacking the aliens, but Alex Hopper only receives a Silver Star (3rd highest award) for saving the world?
Factual error: When Hopper orders to drop the port anchor during the final battle, the chain changes between being stretched and taut from scene to scene.
Factual error: After getting his silver star, Hopper is spoken to by a special warfare commander who has the Navy and Marine Corps medal. But the colors are reversed. The blue should be on your left, and the red should be on your right as you stand face to face in front of the wearer.
Character mistake: When Hopper is being chased by the alien and he goes on deck, Rihanna goes into the control room and aims the cannon at the alien's head. Just before she fires she says "Mahalo" which is thanks in Hawaiian. It would have been better to say "Aloha", which is Hawaiian for hello and goodbye, just before she fires the cannon.
Continuity mistake: The USS Sampson has no Close In-Weapons System at the bow when the movie starts, but uses one to counter enemy fire later.
Factual error: By the time the survivors of the JPJ arrive on board the USS Missouri, there are less than 3 hours before the satellite is in position. When lighting off cold boilers, it takes longer than that to get steam up, yet within minutes the bridge is informed that they have steam in all 8 boilers. If it was that easy, all the battleships at Pearl Harbor on December 7th 1941 could have gotten underway immediately.
Factual error: There is a shot depicting the crew physically carrying a large shell from the rear turret of the Missouri to one of the forward turrets. That shell is supposed to be a 16" High Explosive shell which is also the lightest shell fired by the main battery. Those shells were roughly 5 feet in length and weighed 1,900 pounds and yet we see one being shoulder-carried by 6 men. They are also not utilizing the equipment designed for the purpose of moving these shells.
Factual error: During the ITV News "UFO Landing Confirmed" breaking news scene, the lower caption shows the text "Amateur footage confirms rumors". ITV News is a British news network and would spell 'rumors' as 'rumours'.
Plot hole: The Tomahawk Cruise Missiles the Arleigh-Burke Class destroyers carry have a range of approximately 1500km. As soon as Alex got the message from Sam, they could have blown that Saddle Ridge communications facility to kingdom come with just a few cruise missiles. They didn't need to get in range because the entire dome surrounding the Hawaiian Islands was smaller in diameter than the range of the Tomahawk Cruise Missiles. Cruise missiles have internal guidance, so they wouldn't rely on the radar, which was jammed.
Factual error: The first time the film displays the name USS John Paul Jones during the RIMPAC exercise it is shown as a destroyer with the hull number 65 (DDG-65 is USS Benfold) instead of 53.
Factual error: Loading the projectiles and powder in the 16 inch rifles is done using a ram. The projectiles seem to just glide in on their own.
Factual error: How does the main hero Lieutenant Alex Hopper even get into the Navy as an officer in the first place with a felony breaking and entering on his record? You need at least a Secret clearance and a good moral background to commission as an officer, neither of which would be something Alex can get with a felony on his record.
Factual error: Each turret on an Iowa-class battleship required a crew of 94 to load and fire two salvos a minute. The makeshift crew, including former Missouri sailors (mostly septuagenarians) were equaling that rate of fire with a half dozen men.
Factual error: Towards the end of the movie, an Australian F/A-18E Superhornet is shown destroying the aliens, complete with Australian pilot. Firstly, the Ensign displayed on his helmet is incorrect. Australia doesn't operate any of those aircraft, only 2 seat F/A-18F and older F/A-18A Classic Hornets.
Continuity mistake: The missiles fired at the aliens during the boardgame inspired scene, are shown to be a Standard Missile (SM-2) when leaving the launcher, then a Tomahawk cruise missile when flying towards the aliens.