Continuity mistake: Mike is unpacking his things and puts on his glasses. He stares at the door in awe because he sees Mac standing, but the reflection of the glass shows that there's no one there.
Audio problem: Eric escapes from the cops in McDonald's and he says, "Well done, Mac" but his lips are saying something else.
Continuity mistake: In McDonald's, Eric holds Mac by the neck, in the next shot he holds him under the armpit, without having had time to make the movement.
Continuity mistake: When escaping from the cops, while holding onto the truck and zooming down the road, Mac is on Eric's lap, bare chested and with a couple of rags on his lap. Then Eric throws away the rags, but in the next shot Mac is covered in clothes that have appeared from nowhere.
Continuity mistake: When the neighbour and her mum are in the car waiting for Eric to come out of the house, one of the cops behind turns his head and stares at the car, but in the immediate wide angle his head is in a different position.
Continuity mistake: The position of the rags that Eric throws on the road, when escaping from the cops, differs between shots.
Continuity mistake: When the aliens throw the pyramid of cans, some signs also fall on the floor, yet they disappear in the wide angle.
Plot hole: The Alien family finds itself surrounded by armed cops, scientists, and helicopters yet the next time we see them, some seconds later, is walking around some deserted area. If the Government set them free there's no point in the chase of Mac. On the other hand, if the family managed to escape, then the scene with them defenseless in the supermarket is absurd. No explanation whatsoever is given to this really important part of the movie.
Continuity mistake: Eric follows Mac's footsteps and opens the fridge. A bunch of glasses fall on him, none inside the fridge, but when he closes the door there's one in the fridge.
Continuity mistake: When Eric is playing with the remote control car, there's a toy plane to his left, which keeps changing to a yellow truck and back to a plane all the time.
Plot hole: Mac tries to escape from the NASA premises reaching the closed electrified fence. In the next shot, couple seconds later, he has managed to appear on the other side, outside on the street. This is not possible since Mac electrocuted himself and burst like a balloon when he touched the fence.
Continuity mistake: When Eric's brother is leaning outside of the van to haul his brother, in the close-ups the baddies disappear from behind, only to appear in the next shots.
Continuity mistake: During the vacuum scene, the hose keeps swapping from being over Eric's shoulder to under his armpit. This takes place in really short time lapses.
Revealing mistake: In McDonald's when Mac stretches his arm, notice that it's separated several inches from his body and much thicker, and is really a big sleeve coming form under Eric's armpit. In fact, you can see Mac's real arm next to his body, hanging down.
Continuity mistake: During the windshield scene, a brown pickup truck smashes the back of a white car. Half a second later, the pickup is seen crashed against the front of the car, only to change to the initial position when the pile-up occurs.
Audio problem: In McDonalds, Eric tells his brother "Mac is here", to which he replies, "I don't believe this", but his mouth isn't moving.
Audio problem: When Mac grabs the Coke at McDonald's, the kids say, "I don't believe it" and similar things, but their mouths don't move.
Continuity mistake: When Mac is on the windshield, one of the close shots shows that his hand is bent and up, yet on the immediate wide angle it's straight and along the glass.
Audio problem: When Mac escapes the NASA lab, the helicopter pilot over him is informing about the surveillance, yet his mouth isn't moving.
Continuity mistake: When Mac's on the windshield and the car is dodging traffic, the co-pilot kid appears and disappears.
