Revealing mistake: At the end when April and Kyle are killed, they are thrown in a hole back first. When they are shown, they are neatly positioned beside each other. April even has her knees bent up and Kyle has his arm around her waist meaning they obviously positioned themselves for the final shot.
Continuity mistake: When April shoots the alien, they all go outside to look at it. Behind them, you can see the windows boarded up, but they don't board them up until later in the movie.
Other mistake: At the beginning of the movie, a woman runs to the store to get help. She uses the pay phone booth outside. The UFO takes her and the whole booth. A minute later, the booth crashes back to Earth. The next morning, the sheriff finds her wallet in the debris. She wasn't carrying it and didn't have a purse or pockets.
