Continuity mistake: When Sam is in his bedroom, after he finds the Cube sliver it falls and dramatically burns a hole through the floor into the kitchen. But Sam's bedroom is over the living room (there is nothing on the ground floor below Sam's elevated bathroom, and in the first movie Jazz hides in this open space), and the kitchen is actually located between the den and dining room, at the other end of the house. If they were to follow the actual floor plan of the house, the Cube sliver would have landed in the area of the piano in the living room, but where would the fun have been in that? (00:12:30)
Plot hole: During the later parts of this movie there is much talk about 'continental displacement' and this appears to be happening in the film. The Earth's crust is falling apart because of the heating of the inner core, and all the cities seems to be falling apart since the ground can no longer hold them. When our cast finds themselves surprised to be already over China when they figured to be over the ocean, it is explained that Asia has actually moved from where it was. If this phenomenon is taking place globally, how come the monks in China don't seem to have been disturbed at all? In fact the bell the monk rings as the ocean approaches hasn't even been shaken. The arks are built in between the mountains, but the mountains are apparently fine. Shouldn't they be falling like the rest of the crust?
Plot hole: Inmediately after Jamie Foxx finds the bomb in the city hall, and he says, "We don't tell the mayor anything", we see Gerard Butler arriving to his property next to the prison, and finally he enters his jail cell. So, in the time between Gerard Butler's arrival to the property and his entrance to the jail cell, Jamie Foxx thought about a plan, picked up the bomb, passed through the traffic and security checkpoints, talked to the warden to get access to the prison, entered solitary, handcuffed the bomb, and still had time to wait for Gerard Butler's arrival.
Continuity mistake: During the paper cut scene, when Bella is thrown against the table, there are 5 vases of flowers and 3 sets of candles. After she hits the table she lands against one of the vases and knocks the 2nd one to the floor, but the next shot shows only one vase left upright. (00:14:50)
Continuity mistake: In the scene where Parker is shown playing golf on the indoor golf course in RDA, the first time he hits the ball, there are two other balls lying on the course side by side. In the next shot, two are distant apart and in the shot after that, they are in their original position. (00:12:15)
Other mistake: When Marcus, Kyle and Star are at the petrol station, a flying HK and the giant Harvester robot are able to appear just outside without making any kind of sound. In every other scene of the Harvester and the HKs however, they both make an incredible amount of noise. (00:37:40)
Continuity mistake: When the house first becomes detaches from its foundation and becomes airborne, Russell is nowhere to be seen, although every angle of the house is shown, including underneath, the front porch and the back porch. He knocks on the door and tells Carl he chased a "snipe" under the porch - but he cannot be seen after liftoff and prior to knocking. The same thing happens near the end, when Dug claims to have hidden under the porch.
Continuity mistake: In the dormitory, when lovestruck Ron is going gaga over Romilda, he is wearing a brown sleeveless tee shirt and its tan trim has many holes. When Harry brings Ron to Slughorn, Ron is still wearing that tee shirt, but now some of the holes are gone and the rest of the holes have changed position. (01:26:50)
Other mistake: At 1:39:14 the bomb arms, 32 seconds later at 1:39:46 (two seconds after it should have blown up) Dan and Molly jump from the helicopter. Then 10 secs later at 1:39:56, the plane FINALLY blows up after giving them those extra 12 secs to jump and conveniently make it to the pool below.
Factual error: During the first tunnel sequence, all the cars travel very far into the mountains, turn lots of corners, yet not only is Gisele still able to speak to them over the radios, their GPS still works. GPS signals invariably need a clear 'sight' of the sky and can penetrate light cover, but most certainly not that depth and cover. (00:58:05)
Continuity mistake: When Trent and Bree are having sex, the ceiling fan is on then off.