At the end of the movie, when the car crashes head-on into the light pole, Frank Enley is thrown forward by the impact. He is next seen lying in the street several yards to the rear of the car.
At the end of the movie, Joe Parkson bends the knee of his right leg, the 'lame' leg he has been nearly unable to bend throughout the entire story.
As Parkson (Robert Ryan) gets into the rowboat, there is a stiff breeze, the water is choppy, and a cloudy sky is 'threatening'; a second later, after the tender pushes the boat away from the dock, the lake is calm and breeze-free, and the sky is clear.
When Enley and his wife are awakened by their child's nightmare, the time on the nightstand clock is about 2:25. Later, she's awakened when Enley leaves, but the time has gone back to 1:25.
When Enley leaves Pat's room, the lighting on Pat suddenly changes from very shadowy to bright for no apparent reason.
At the beginning, the bus drops Joe off in Santa Lisa, and a policeman stops him from crossing the street because a parade is coming. The bus would not drop off passengers in the middle of a parade route. Not only that, but the bus headed directly into the oncoming parade.