Revealing mistake: When Howard is reading the book about how to "score with babes" his lines are on a piece of paper on the page. You can see this by the different color papers. (00:46:25)
Revealing mistake: When Ed and Dexter are in the ventilation shaft, watch when they fall in the trolley thing. If you look carefully you can see Ed's wig hanging on the edge. It's got a good burger hat on it.
Revealing mistake: In the scene where the geoligist's husband calls her from the L.A. airport to say he's going to try to make it home, a strong aftershock collapses the wall that the pay phone is mounted on - as this occurs you can see cables attached to the wall pulling it over.
Revealing mistake: Near the beginning of the movie, when all the zookeepers are being 'savaged' by bandicoots and chipmunks, a woman falls down and really hurts herself. Later in this scene, the woman is dropped from her stretcher, except before she is dropped, there is no-one holding on to the end of the stretcher nearest to us.
Revealing mistake: When Nick tells T. that he wants to give the money back they start fighting. Nick's sleeve gets almost ripped off, but before this happens you can see that the sleeve is stitched on rather loosely. (01:21:25)
Revealing mistake: When the toilet cabin is pulled upright the chain hangs through long before the cabin stands vertically. (00:47:25)
Revealing mistake: When Fred Randall is in the motion sickness machine (the one that spins around horizontally), you can see the three people in the observation centre above at one point. Look at them closely, because they are fake.
Revealing mistake: When Korda crashes the Explorer through the police barricade, his car hardly takes any damage, proving the barricade is far more lightweight than a real one.
Revealing mistake: When Katherine is doing cartwheels, her dress stays down in relation to her feet. It doesn't ride up or flap towards her upper body.
Revealing mistake: During the flashback scene where Max is describing the night of the kidnapping, the rainfall at the marina is obviously fake. The "rain" is being blown at an odd angle from an off-camera fan, and the surface of the water is practically still with no raindrops. (00:40:50)
Revealing mistake: When Gustav starts shooting Pest and he jumps into the river, you see that it is not Pest who jumps in.
Revealing mistake: Near the end of the film, when Dacascos is fighting that other guy from Hong Kong, if you watch just after he does this smart kick, the guy's actually an Asian stunt double, and a lot shorter than Dacascos (best seen on the DVD putting it in slow motion just before).
Revealing mistake: When Ernest is climbing up the chimney to get the mouse, the chimney shakes/wobbles slightly, showing us that it's made of rubber.
Revealing mistake: Whenever there is a bird's eye view of the town, you can see that the far backgrounds are paintings.
Revealing mistake: When Alex is walking back from Mrs Hess' after shovelling her drive, you can see the "crooks'" car lights waiting for their Q to enter the street in the top left. (00:10:10)
Revealing mistake: Throughout the entire film, it's quite obvious that most of the "snow" is fake. It just doesn't quite look right. It often resembles mashed potato flakes or Christmas tree flocking instead of real snow.
Revealing mistake: When Magoo is skiing downhill, and the camera points directly at him whilst skiing, if you look to either side of his skis, you can see the tyre tracks of the vehicle towing him.
Revealing mistake: When Brad and Caroline are running off in the taxi, across the border to PA, it is obvious that the lighting inside the cab are studio lights from the traveling crew, as natural moonlight would not reflect so strongly inside or out of the cab, at that speed.