Goofs

When Mike boards the mothership a second time to get more information about the Visitors, he is seen with a laser weapon in its holster. However when he enters the mothership's water storage area, it disappears.

When the voice is counting down in multiple languages the Greek part is not correct: enea (9), theka (10), octo (8).

When the mother ship is approaching and we see a group from behind as they are watching it, Robin Maxwell leans in to her mother and puts an arm around her. In the reverse shot, she is hugging her mother. Then we cut back to behind them and she leans in and hugs her again. This is because there are two different actresses playing Robin during this scene. The shots of Robin from the front are of Blair Tefkin, who played Robin the entire duration of the series. The shots of her back during this scene are of Dominique Dunne, who was strangled to death by her boyfriend after a few days of shooting. Director Kenneth Johnson kept the reverse shots in her memory.

In the shuttle right after Mike escapes with Robin from the mothership, Mike loops the shuttle, and there is shot of them upside-down. Robin raises her arms, apparently to keep from falling out of her seat, but the entire time her hair rests on her shoulders as if right-side up.

Whenever a squad vehicle is firebombed, the cockpit window shreds like its made of tarp or paper instead of shattering like glass.

The Shot of the mothership hovering over the city (right after the scene with The Maxwell family reunited) shows the sun in the background however the sunlight reflected on the the mothership comes from a totally different direction.

When the people watch a live broadcast of "John", the alien leader, film speckles and scratches appear on their televisions - revealing that they are clearly not watching "live" television.

In the shuttle after Mike escapes with Robin from the mothership, Mike loops the shuttle, and Robin squeals, but her mouth never moves.

The aliens say they need sunglasses because Earth is too bright. However, most of the mothership is brightly lit. Also, it's mentioned in "character error" that the aliens are reptilian thus could only survive in cold weather, the reverse is true. Reptiles need very hot weather. So their home planet would likely have a very bright sun.

When Daniel Bernstein starts pouring champagne for his family, the boom mic is reflected in the glass of the portrait above his head.

A Resistance member says that cold-blooded animals are better adapted to cold weather. The opposite is true. If the Visitors were really cold-blooded, they couldn't survive in extreme cold as depicted in the movie.