Revealing mistake: At a certain point we see the arid, dry Santa Monica Mountains of Los Angeles in the upper left of the picture with a huge high-tension electrical tower at the summit. The film is set in 1912 in Iowa, a green, rainy state which is also completely flat, with no mountains. Then again, we see the arid, dry Santa Monica Mountains in the upper right. (00:08:27)
Revealing mistake: Godzilla just reached the coast and is fighting a horde of toy tanks. When she sets foot on the base and swings her tail at the control tower, you can see that the tower is pre-broken in the middle, already all cracked and ready to fall apart at the center when Godzilla barely touched the tip. (00:15:10)