Revealing mistake: At one point in the final battle, as they are approaching the cliff where the fight's climax will take place, during a wide shot, King Kong and Godzilla are both two action figures that are hitting each other.
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)