Continuity mistake: The film starts in Muncie Indiana. There is a scene in the hills near the town. There are NO hills near Muncie, it's flat as a board.
Other mistake: In the climactic scene at the end of the movie when the alien mothership flies over Devil's Tower and the base, there is a shot of the mothership's shadow creeping along the ground, enveloping the shadows of the crew there. It's a dramatic shot, but since the mothership was not between the ground and the light source (the stadium lights of the base) it should not be blocking out the light, or creating a shadow.
Factual error: Parts of the scene where the brightly lit alien mothership passes directly over Devil's Tower are shot with the camera looking almost directly up, as would be the view from the people below. In these scenes, Devil's Tower remains totally dark despite having this huge light source directly above. The mothership is so huge that a shadow cannot explain this darkness.
Continuity mistake: In India, Claude asks the Guru where the sounds came from, while a huge crowd walks along the desert. When a man in blue addresses the crowd to ask them, the crowd on the right side is gone, and the ones on the left aren't walking but standing perfectly formed like an army.