Watching the movie as many times as I have, you tend to notice a few inconsistancies...
1. As the two look-outs get on the big wheel the thin guy with the ventriloquist's dummy sits on the right. But later in the film he is on the left.
2. When Tim Matheson and Nancy Allen are flying in the plane, in a couple of shots, the pilot seat window has a bullet hole, other times not.
3. The amusement park ferris wheel lights stay lit, even AFTER it is knocked from its foundation by the Japanese submarine and rolls down the pier. Without electricity, that is impossible!
4. After John Belushi crashes his plane, he opens his parachute. The wire pulling the chute away from him is visible.
5. The front door of Ned Beatty's house is totally intact while it slides downhill. But in several scenes, the front door was broken several times.