(at around 46 mins) Geno has lost his left shoe running through wet concrete to reach Frankie, but at 10:17 his shoe is back on his left foot without his having an opportunity to retrieve it (he is always either on camera or Frankie is looking up at him).
In the archery scene, the driver's window of Phil's 1961 Chevrolet Parkwood station wagon is clearly rolled down at 01:34:51 before Frankie gets into the car. Moments later at 01:35:21, as Phil is menacing Frankie from outside, the window is suddenly closed.
The newspaper headline says Franky is ten years old. However, the caption below Melissa's picture says she was killed in 1951, and the sheriff mentions she was killed "ten years ago". According to Franky's tombstone, he was not born until 1953. The math doesn't add up.
When Frankie is praying in front of a picture of Jesus, towards the right there is what looks like a toy dinosaur. But in the following shot the dinosaur has disappeared. This is an apparent goof resulting from the compression of distance by the telephoto lens used to achieve a closeup at 49:17 where it appears that the picture of Jesus and the statuette of Godzilla are side-by-side when the statuette is actually some distance behind the picture as can be seen at 49:26 where the statuette is behind the picture at the left edge of the wide screen frame.
The distance between Frankie's bike and the porch changes in the opening shots of him getting ready to leave for school the first time. This is an illusion caused by the use of telephoto lenses that compress depth (distance from the camera) but not breadth (distance left to right across the scene the camera is viewing). At 05:46 where the bike appears more than 20 feet from the porch, the distance is running across the camera's view, but 06:20 where the bike appears only a few feet from the porch, the distance is running directly away from the camera.
Director Frank LaLoggia mentions that in the strangling scene (at around 1h 40 mins), the cord was already around her neck and was hidden by her position and the lighting to achieve the effect that this man was evil to the point of almost being a spiritual presence so he could do anything.