When seen in the mirror maze, Karen is wearing white tights. When she returns to the chapel, they are gone.
When Jan goes to see Mr Keller, she leans her bike against the right hand door post, but when she leaves, she collects her bike from the opposite door post.
When Jan and Mr. Keller are in the chapel waiting for the rest of the people to arrive, she looks through a stained glass window. It is a big missing piece she looks through, but when they show the rest of the people turning up, it shows the lead in the glass minus the stained glass rather than one big missing piece.
The car that falls into the ravine is clearly a model as it has no axles or drivetrain.
When the mother gets scared about what is happening to her daughters and decides to flee, you can see a hose behind the car providing the rain just before they drive onto the bridge.