Plot hole: After his mother's death, Peter sets a camera up outside her therapist's office, so he can see who goes in and who comes out; he thinks his mother's killer might be one of the doctor's patients - a tall woman with long blonde hair. All he sees is people going in and people coming out, and then he sees her - the tall blonde. Problem: He never saw her going in, only going out, which is critical, because the killer is the therapist - a tall man - wearing a long blonde wig and make-up. Of course no-one says anything about "We never saw her going in, only out, so it must be the therapist!"
Plot hole: When the fog finally hits the lighthouse and is seeping in, the generator is hardly audible vs. how loud it was when it was first started.
Plot hole: The film takes place around 1980, i.e. when it was filmed. But Steve Railsback appears too young for the Vietnam veteran he is playing, and in any case he has meant to have come back from the war, immediately committed a crime, and been on the run since. This would only be possible if he had been on the run for a decade, with the police in hot pursuit for all this time: that is extremely unlikely. These inconsistencies are actually a reflection of the fact that the film was scripted a decade before it was shot.
Suggested correction: Cameron is not too young for the timeline of the film. Steve Railsbeck was born in 1945. The first US troops arrived in Vietnam in 1965. If Cameron did a one year tour of duty between 1965 when he was 20 and 1969 when he was 24, that gives him a year to be discharged, return to the USA, commit a crime, and be on the run for ten years or more by 1980. Wikipedia lists 120 criminals who have been on the run since 1970 - and that's just the famous ones.
