Animal sounds heard along the river in the scene where the private detective hands over the suitcase to Mrs Bowden are not those of the local fauna. One can distinctly hear the laughing voice of the kookaburra, a bird found only in Australia.
When Sam is at the boat dock he goes into the shop and gets some thinner. As he is leaving the shop he has the thinner in his left hand. Then when he confronts Caty the thinner is gone and then he takes his daughter down the stairs the thinner is never seen again.
When Nancy is being chased by who she believes to be Max, she runs into a room filled with lockers-we see her Right hand pressed up against a row of lockers and she is wearing a ring. In the very next frame, the ring is absent from her finger.
For some strange reason, just after Sam shoots Cady, the shot of Cady from Sam's POV shows the branches of a bush superimposed on the bottom and left side of the frame. The tipoff is that when the camera moves the branches of the "bush" do not - they move along with the camera, as if they're glued onto the frame (which they are).