Revealing mistake: When the airplane is coming in for a landing, we see an exterior shot of the plane shaking violently well before it has touched down. Clearly the "earthquake" effect is achieved by merely shaking the camera.
Revealing mistake: After failing to spin the loop in the motorcycle the first time, Miles tries again. He starts driving towards the loop, and after he finishes the first half, if you look carefully, the bike then falls out of the loop. For the rest of the scene, he continues to ride the bike around the second half of the loop anyway. The shot of him riding towards the loop was probably a previous take.
Revealing mistake: Near the beginning, after a couple of small earthquakes, Fred comes flying out of the dam elevator shaft with a whole heap of water, dead from drowning. But you can see him lift his head out of the water seconds before his friend turns him over and finds him definitely dead.