Factual error: It is stated that Miss Trunchbull competed in the Olympics in shot put, javelin, and hammer throw. According to her jersey those were the 1972 Olympics. The hammer throw wasn't added as an Olympic event for women until 2000.
Visible crew/equipment: Two wires can be seen attached to Lavender (because light shines on them) as she floats back to the ground after the Trunchbull charged towards her. This is only visible on video, and has been taken out of the DVD, although you can (barely) see the shadow of the equipment letting her down on the wall behind her.
Continuity mistake: When Ms. Trunchbull throws Amanda Thrip over the fence, her trousers get all dirty. And then in the next scene where Ms. Honey is doing Amanda's hair, her clothes are clean again. (00:41:38)
Continuity mistake: In the scene halfway through where the FBI agents are searching the garage, the door on the camcorder opens twice. Once before he turns around, then once more as he turns around and the tape comes out.
Continuity mistake: When Matilda makes the chalk write the message on the blackboard, the writing changes. Watch the "Agatha," especially. The handwriting changes and the comma changes length, as well as most of the message changing. Also at the end of the message Matilda "writes" two long lines under it, which cross over. Yet later when Miss Trunchbull flies off the globe you can see there is just one line under the message, not two. (01:20:20 - 01:23:00)
Deliberate mistake: When the Trunchbull is drinking from the glass with the newt in it, you can easily see that she doesn't actually drink anything, as the water level stays exactly the same. Logical, as the newt is real, but it's still very obvious because she drinks for about 15 seconds. (00:46:55)
Continuity mistake: When Miss Trunchbull is in her home searching for the person in her home, she jumps down off the second floor to the first without using the stairs, a chandelier falls to the floor and shatters. Moments later when they show that area again, the chandelier is gone from the floor, in fact it's seen back up on the ceiling.
Continuity mistake: When Bruce Bogtrotter eats the cake and everyone starts to yell out 'Go Bruce,' there are several bits of cake left on the tray. Bruce stands up and moves to the front of the stage yelling. When he gets back, he licks the tray, and all the bits of cake are gone.
Audio problem: When Zinnia combs back Harry's hair with the grey stuff in it, we see her lips moving, but we hear Michael's voice.