The bulldog changes sex; when urinating in Harry's room it is a male, yet when it warns Harry about the hitman behind the door it is a female.
Jennifer's last name is spelled "Spenser" on the sign in the gallery but "Spencer" in the end credits.
When the young uniformed officer is shot during the bank robbery, he reaches to the left side of his forehead. Later, in the police station, he is seen with a bandage on the right side of his forehead.
In the coffee shop scene Loretta keeps pouring sugar into Harry's coffee but the amount of sugar in the jar stays the same.
During the coffee shop scene, Loretta has a pencil above her ear that disappears and then reappears.
Amusement parks that are closed or have been shut down do not have power. Each ride needs many workers to operate. They just can't be "turned on," even if the power grid was accessible or active.
Harry tells his pal that his new Auto-Mag pistol fires a 300 grain cartridge. There is no such thing. He should have said 300 grain bullet.
The motorcycle thief would likely have multiple injuries after crashing.
At the end of the movie, Harry advises that officer that the gun recovered from Mick's dead body belonged to Mick, rather than to Jennifer. If it were discovered that the gun actually belonged to Jennifer, she could face prison time for the murders, and Harry could be charged with falsification of evidence.
In the film, a few henchmen are seen moving limbs (or face) after being shot through the head (in brain matter area) before going down. An impalement there would immediately stop the 'motor' activity.
When Callahan is attacked by the four Mafia hit men, they start firing at a wooden box they suppose Harry is hiding in. One of them fakes shooting a pistol, mimicking the recoil, as it is clear that the gun doesn't fire at all.
When attacked by the mafia, the charges are visible on the car's windshield before being "shot."
When Harry is target shooting outdoors, the target in the long shots is in shadow under trees, but upon close-ups it is clearly in full sunlight.
When Harry "rips" a page from the teletype machine, it's clear that the page had already been separated.
When Harry nails up his target in the woods Horace shoots at it first, with a shotgun, and blows two large holes in the target nearly cutting it in half. Moments later when Harry shoots at the target with his Automag the target no longer has the shotgun holes.
When discussing the abrasive woman Callahan met in the bar, he tells the local officer that he'd, "brushed her, across her." This was clearly a blown line but, as is characteristic of an Eastwood-directed film, he didn't bother with a retake, knowing that the audience wouldn't mind.
Bradford Dillman, who played Capt. McKay in the previous film _The Enforcer_, seems to be playing the exact same character here, except he's named Capt. Briggs. Even more confusing is that Briggs was the name of _Hal Holbrook_'s ill-fated lieutenant in the second Dirty Harry film _Magnum Force_.
(At around 28:25) During the shootout scene on the street, the four mob hit men shoot holes in many cars with their machine guns. In one instance, the shots on the car's window are clearly coming down from high above with a 45-degree angle, as if they are fired from a balcony, even though the men who are supposed to be shooting are on the street, same level as the car.
As Horace exits the car while visiting Harry, who is about to begin target shooting in the woods, one of the Panavision cameras is clearly visible, reflected in the car window, as well as Eastwood's son, who was visiting the set.
When Jennifer visits her exhibition and approaches the woman in the purple dress, reflections of two crew members - one being the director, Clint Eastwood - can be seen in the acrylic glass on the right, one of which quickly kneels to hide from the shot.
When Harry first arrives in San Paulo and the alarm bells ring, just before he starts chasing the thief, a camera crew member is reflected in the chrome of his side mirror. A man holding a boom mike is visible. Then, as the car starts driving, the boom mike is once again visible in the rear side window.
Harry arrives at the fairground to confront the villains at the movie's climax. But he wouldn't have known where they were going to be.
Jennifer told her sister that she bought a gun and killed with it. At the end, Callahan allows the same gun to be taken in for evidence to match ballistics, and he tells the officer it belongs to Kruger. Problem is, police will match the registration of the gun to Jennifer.
When Harry arrives at the diner and interrupts the hold-up, the robbers seem to know somehow that he's a police officer, even though he's driving an unmarked (but somewhat older) model car, and wearing a casual suit and not a uniform. Also, as soon as Harry walks out the door, they continue the robbery even though Harry's car is still clearly seen parked there, meaning he hadn't completely left yet.
Meathead changes genders several times through out the film. Male when he hikes his leg in Harry's hotel room, female when running just before meeting Sandra Locke, but male right after. Female again in Harry's hotel hallway when the thug tries to kill Harry.
Jennifer lacks any kind of stealth when she goes on her killing spree. First, she drives her car to Ray Parkins' house with her headlights on, then parks right n front of the house where Harry can see it right there in the open. Somehow, Ray and Mick are never alerted to this, nor are they when Harry drives up so few minutes later. Then, Jennifer goes to kill Alby, and parks her car right in front of the house instead of somewhere out of the vicinity.