One of the characters tries to join the armed services, but says that they are short of equipment. The air force may have been short of modern fighter jets but both the army and navy had huge quantities of ships and equipment, including weapons left over from WWII. enough small arms to arm not only an enlarged army, but the civilian population .
The Soviet bombers shown dropping the atomic bombs are in fact American B-29 superfortresses. In fact in the American retaliation raids the same B-29 planes are shown. This reveals stock aircraft footage was used for both.
The stock combat footage from World War II shows the supposed Russians using Kamikaze techniques.
They kept referring to Hoover Dam as Boulder Dam in that sequence of the movie. The fact is that it was Boulder Dam from 1933 to 1947 and then it was called Hoover Dam from that point on.
This film shows Boulder City Nevada as a flatland farm community downriver from Hoover Dam being flooded by water after the dam is bombed. Boulder City is on a hilltop seven miles from the dam and some 1300 additional feet in elevation.