Continuity mistake: When MAC is blown by the helicopter, he lands on a man's windshield, and the man has to start dodging traffic. Between shots the traffic he is dodging changes. (00:10:45)
Continuity mistake: When Mac's on the windshield and the car starts to dodge cars, one shot from inside the car shows the alien has disappeared.
Continuity mistake: When Eric following the wet footprints outside, to the edge of the lawn, the footprints change in appearance drastically, between shots. (00:23:15)
Continuity mistake: When Debbie's mum stops the car, as MAC speeds past them on a remote control car, she parks on the right side of the road. In the next shot her car is on the left, then back on the right. (00:51:00)
Continuity mistake: When Eric wheels himself outside in his wheelchair, to follow the footprints, as he exits the double doors, he goes down a ramp. Later, when his brother walks through the doors, the ramp has vanished. (00:23:10 - 00:24:10)
Continuity mistake: When Debbie is putting Mac, who is hidden in a teddy suit, into the back of her mum's car, as her and Eric leave to go to Brittany's birthday party, the car window changes from halfway rolled up, to fully rolled up between shots. (00:57:55)
Continuity mistake: When we see the two holes drilled through the wall, by MAC, there is nothing above the holes being made, yet in all the following shots a large painting is above the holes. (00:29:10)
Continuity mistake: When Eric and the others find the MACs' in the old mine, they give them drinks. The MAC by Eric then begins to stand up. Between shots a long strip of black bin liner appears over his legs. (01:18:50)
Continuity mistake: When Eric and Mike find the newspaper clippings and papers left on the table by MAC, to try and tell them about where he came from, the papers' positions change between shots. (00:47:35)
Continuity mistake: In the van chase scene, Mike is hanging out of the window trying to pick up Eric in his wheelchair, as they flee from the running cops. As Mike tries to pick up Eric, his sunglasses keep disappearing and reappearing. (01:07:15)
Continuity mistake: After offering MAC the drinks of water, Eric pulls the drink away from him twice. (01:08:05)
Continuity mistake: After the delivery guy puts Eric's TV down, it changes position in the following shot, and so do the cables on top of it. (00:20:30)
Continuity mistake: At the beginning, when the NASA spacecraft lands on the MAC planet, there are three silver antenne around the side of the craft which are absent in some shots. (00:02:15)
Continuity mistake: When Mike is getting ready to pick up Eric and haul him into the van as they flee from the cops, in exterior shots Debbie is leaning out of the window, but in interior shots of the van, she is sitting inside, and the van window is closed as well. (01:07:20)
Continuity mistake: When Eric first talks to Debbie, as she stands on the balcony, the position of the bracelets on Debbie's right wrist keeps changing. (00:23:35)
Continuity mistake: During the dance at McDonalds tables and chairs suddenly disappear from the place and are replaced by dancers.
Continuity mistake: When the MACs' are sucked into the NASA spacecraft, an explosion occurs, causing a grey cylinder capsule to fly off. In the next shot the capsule is attached to the craft again. (00:04:25)
Continuity mistake: When Eric is playing with his remote control car, he stops and takes the battery out. In the next shot, when MAC touches the car, the car is now in a different position. (00:20:00)
Continuity mistake: In the panning shot of the NASA lab, the clock's minute hand can be seen on the half hour mark, yet in the close-up of the Professor, the time reads eight twenty. (00:06:50)
Continuity mistake: When Eric is about to wake up from his coma his jacket swaps from very open to slightly open between shots.