At 1 hour 15 minutes, the car that crashes into the lake is a different make and model than the car used in the rest of the movie.
At around the 38 minute mark, when the camera is panning into the living room to a couple making out, the crew are reflected in the patio pane door.
At about the 1 hour and 18 minute mark, the camera man is visible in the sunglasses reflection during the alien attack.
When Sally Foster crashes her car in the beginning, the stunt driver wearing a safety helmet can be seen through the passenger window.