During Veronica's conversation with Mike at 8:30, the level in her water bottle jumps up and down from shot to shot.
When Keith visits Aaron, the guard who is in the room with them is reflected in the mirror standing opposite the mirror. When he's seen on camera, he is clearly standing by the door, which is on a different wall.
When the school bus crash happened, the bus is in pieces in the water. Later, Keith and Veronica learn that there was a dead rat taped to the bottom of one of the seats with a bomb. When Keith goes to examine the bus, the bus is fully intact except for missing windows and some damage. And later, when Veronica finds the rat in their freezer, the rat is fully intact.
When Veronica (Kristen Bell) is doing the video chat, the preview window of her own video shows what the camera for the TV show records and not what the webcam records. You can even see the webcam clipped to the notebook in the preview window.
The interrogation room where Keith and Aaron talk has a sign on the inside of the door which says 'interrogation room'.
Veronica (Kristen Bell) works out that Amelia (Erin Chambers) must have had a fake ID to be able to drink during her Europe trip, as she was only 20 at the time. There are no countries in Europe in which 20 is below legal drinking age.