Revealing mistake: When the UN team arrives in the Gobi desert, there's one shot where the helicopters and trucks are parked. They're supposed to be moving, but you can tell from the way the flags are moving that the wind is only coming from the helicopters.
Revealing mistake: In the scene where Ronnie cuts out a newspaper article about the UFO sightings, the night after Roy's first glimpse of the UFOs, two identical articles on Star Wars (1977) are on either side of the UFO article.
Suggested correction: The articles aren't identical, they are continuous. I read them. Only the title, "wars" is identical.
Revealing mistake: The morning after Ronnie and Roy's big fight, Roy starts cleaning up his clay "sculpture." Before he pulls its upper portion off, you can see the pre-made seam (which is poorly disguised by the clay) where the top is attached to the bottom. When he tears it off, the lower portion is perfectly smooth and flat on top (simulating Devil's Tower) where it was obviously pre-cut.
Revealing mistake: When the gigantic mother ship appears and sweeps over the rendezvous base at Devil's Tower, the camera cuts to look straight up at the advancing craft as it blocks out the starry night sky. Watch carefully to see some stars passing right through the leading edge of the mother ship, revealing a flaw in the traveling matte effect.
Revealing mistake: The huge UFO opens its door and a brilliant light comes out, but from the opposite angle, the reflection on the people's glasses is a black landscape and a tiny spot of light.
