When Captain Cho gets into his vehicle at the beginning of the first chase scene, he closes the door with a loud slam. The door is clearly a standard HMMWV soft door with a plastic door handle, and would not make such a noise.
About 15 minutes into the movie, when Jed and the guys escape in the pickup truck, they go off-road. The cat-back exhaust is visibly missing. When they get back on the road, the exhaust is suddenly hanging down and dragging on the ground. In the next shot the exhaust is gone again.
After Matt yells to Peter in the car to follow them and they are driving through the park, Peter's car pulls behind the truck. In the next shot the black Jeep is behind the truck. Then Peter's car is behind the truck again, and then the Jeep is behind the truck.
The depiction of the North Koreans is inaccurate. The vertical banners are missing the blue stripes of the North Korean flag. The hammer, sickle, and writing brush symbol is used by the army even though it is the emblem of the ruling Workers Party of Korea. Portraits of Kim Il Sung and Kim Jong Il, which are everywhere in North Korea, are nowhere to be seen. The uniforms are not standard North Korean uniforms, and Captain Cho never wears any headgear.
When the Wolverines are about to ambush the Koreans at their town rally, Darrel looks down the scope on his AK74 and the lenses cap on the back of the scope is down, blocking Darrel's view of both his dad, and his true target.
In the deer hunting scene as they observe the lone whitetail buck, the deer has 2 points and a brow tine on his right side and has a total of 6 points. After the buck is killed, you can see the right side of the rack and now he has 4 points and a brow tine on the right and is probably a 10 pointer.
The North Koreans' invasion plan relies heavily on taking out U.S. Central Command. CENTCOM covers the Middle East. Its name derives from the fact that the Middle East is in the center between Europe and the Pacific, not because it is "centrally" vital to the U.S. military. U.S. Pacific Command would be responsible for North Korea, and U.S. Northern Command (named for North America) would be responsible for defense of the continental United States.