Some scenes show electrical lights over the pool tables. Light bulbs were invented in 1878 but Tombstone did not have electricity until 1902. Furthermore, pocket billiards as we know it today (using striped, numbered object balls) would not have been played in the American West of the 1870s, having only been developed in the early decades of the twentieth century; the immediate forerunner of pocket billiards (using solid-colored, unnumbered balls) wasn't invented until around 1900.
The Bird Cage Theater did not open its doors until December 25, 1881, almost three months to the day after the gunfight at the OK Corral, yet in scene 7 of the movie you see Curly Bill Brocious and Johnny Ringo enjoying the show, along with all the Earps, BEFORE the gunfight took place.
Behind the Professor's magic act is the portrait of "Fatima the belly dancer," where the woman's costume top is falling off and exposing her breasts. This portrait, an iconic image featured in many Wild West reference books, was painted in 1882, a year after this scene takes place.
In the opening scene, we see a Winchester Model 1873 being loaded. A round is then levered onto the chamber. The sound is that of a different rifle as the model '73 has a very distinctive "clank" caused by the heavy brass cartridge lifter.
When the group first meets Marshall White and he's explaining how the "Cowboys" run the town, he points out "3 of them over there" by their red sashes. When you look, there are actually 4 men with red sashes.
When Doc Holiday keels over and falls from his horse, there's a substantial amount of blood coming from his mouth as he spits up. Once on the ground and before he's assisted, there is barely any blood present.
Early in the movie, when Wyatt Earp meets his brothers at the train station they stand for a moment looking in a mirror. The reflection of the group shows the there are no shadows on their necks and shoulders. When the camera looks directly at the group one can see shadows on the group's necks and shoulders.
In Doc Holliday's first scene, once he pulls his guns on Ed Bailey, he immediately throws both guns' hammers back. Then, it cuts to a different angle and shows him slowly pull one gun's hammer back again. Then, when he puts his guns down, somehow, neither hammers are cocked anymore.
During the OK Corral shootout, Ike Clanton dives into Fly's Photo Studio, grabs Mayor Beehan's pistol, and begins shooting at the Earps. After the shootout, when Mayor Beehan walks outside to "arrest" the Earps, his pistol is still in its holster on his waist.
When Fred White points out the Cowboys standing by the Crystal Palace he says there are three of them. In fact there are four. One standing talking to a woman, one sitting in a chair dressed in black talking to another woman, and two more standing talking to Behan.
A few scenes prior to the OK Corral shootout, members of the Cowboys gang are seen riding towards town as the sun is low in the sky. In the next scene, as they slowly ride past the Earps who are in front of the sheriff's office, from the Cowboys' perspective the sun's light shines on the Earps from the horizon. When the camera switches to the Earps' perspective, however, the sun's light is shining directly down on the Cowboys from overhead. The camera switches back to the Cowboys' perspective and then the Earps' one more time, and in each case the sun is in different positions in the sky.
After the Battle at the O.K. Corral, Wyatt walks up very close to Behan and stops. When the next shot cuts to behind Behan, Wyatt is visibly much farther from him and is still stepping forward. In the following shot he is up close again.
During the barroom scene showcasing Johnny Ringo's gun handling skills, Wyatt's hand alternates between being on the shotgun under the table and then again on top of the table all while he is conveying the impression of covering the Cowboys.
Wyatt jumps his horse through the window of a saloon and begins shooting. Two cowboys jump up and begin shooting back. As they do, a door opens behind them and Texas Jack and Sherman McMasters burst through and gun them down. In the very next cut, a moment later and from a different angle, the same door is kicked in and Texas Jack and McMasters once again come through it and gun down the same two cowboys.
When Virgil goes outside on the night of the storm after seeing Wyatt and Morgan, the arm of a crane is visible in the background behind the roof of a building. It sticks vertically up in the air, probably for mounting lights.
In the gunfight at the O.K. Corral, Ike Clanton runs from the photography studio and falls to the ground. As he scrambles to his feet, a crew member in a blue shirt and white pants is visible in the background, moving in a crouch from left to right, and goes out of sight behind a fence.
The Iron Springs shootout between Wyatt's posse and Curly Bill's gang is depicted as an ambush by the latter. In reality, the two parties met almost by accident; Wyatt Earp and his men were looking for water and came across Bill and his men, who were camping in the area.
Warren and James Earp are absent in this film, despite their presence in Tombstone. Granted, neither of them participated in the gunfight at the O.K. Corral, which is likely one reason for their absence, but Warren later rode with Wyatt Earp, Doc Holliday, Jack Johnson, Jack Vermillion, and Sherman McMasters in the epic Earp Vendetta Ride.
In one saloon scene, Ike Clanton makes threats against the Earps and Virgil hits him over the head with the butt of his gun. Actually, that took place on the street outside, and it was Wyatt Earp who struck Ike across the mouth with his Smith & Wesson, leaving a small gouge in the lower left side of the barrel of the gun (presumably from one of Ike's teeth).
The 3 Earp brothers, Wyatt, Virgil, and Morgan are shown arriving in Tombstone. In truth, Wyatt Earp, Virgil, and their eldest brother James arrived together. Morgan was still en route, and Warren (the youngest) would soon follow.
At the time of the Earps' arrival, Tombstone is portrayed as a prototypical (i.e. studio backlot) rowdy cowtown, with lots of new wooden buildings. It was, in fact, a mining boom town in the early stages of development. The few wooden buildings were outnumbered by adobe ones, which were in turn outnumbered by tents.
In the film Ike Clanton runs inside Fly's Photo Studio, takes a gun from someone and begins firing at the Earps through the window. Clanton never actually fired a shot during the infamous gun fight. He ran straight through Fly's and out the back door.
Contrary to the film's portrayal, Doc Holliday did not leave the O.K. Corral gunfight unscathed. He received a minor glancing blow to the hip, possibly from Frank McLaury, towards the end of the skirmish.
Upon arrival in 1879, the Earps are greeted by Johnny Behan, the sheriff of Cochise Country. At that time Tombstone was still in Pima County and Charles Shibbell was sheriff. Cochise County was gerrymandered out of Pima County in 1881, when Democrat Behan was appointed sheriff by the Democrat governor. Much of the history involved the conflicts between Republicans (miners, townspeople, the Earps) and Democrats (Behan, ranchers, the "cowboys").
The coach carrying the group of actors arrives with a driver and a man riding "shotgun". Typically, the type of shotgun used at the time was a "coach gun". Coach guns were distinctive in that the maximum barrel length was about 18 inches. The shotgun shown in the movie was conspicuously longer.
Curly Bill Brocius is shown as the leader of the "cowboys"
prior to the arrival of the Earps. In truth, the "cowboy" band was under the control of "Old Man" Clanton until his death, during a rustling expedition into Mexico, about 1-1/2 years after the Earps arrived.
The film shows Curly Bill shooting Fred White in cold blood, being forcibly subdued by Wyatt, but being acquitted due to a 'lack of witness' (presumably because people were intimidated by the Cowboys). In reality, Curly Bill's shooting of Fred White was probably accidental. Curly Bill immediately expressed remorse for the shooting and gave himself up immediately. Wyatt did take Curly Bill away, but more for his own protection as White was popular in town and Earp feared that people might lynch Curly Bill. Contrary to the film, Fred White did not die immediately, but lingered long enough to testify that he himself thought the shooting was accidental. It was White's testimony, combined with evidence that the guns had a hair trigger, that acquitted Curly Bill, not Cowboy intimidation of potential witnesses.
Although a Democrat, John H. Behan (1844-1912) was appointed sheriff of Cochise County by a Republican territorial governor of Arizona, John C. Fremont. This was because the territorial legislature was controlled by Democrats, who had to approve the choice. Fremont (1813-1890) was himself an appointee of Republican President Rutherford B. Hayes. The famed explorer was the first presidential nominee of the Republican party in 1856.
In the gun fight at the O.K. Corral, gun shots are being fired from all participants and yet the horse still rears at a blast from Doc Holliday's shotgun later in the battle. That gun was louder than the others, and possibly closer to the horse.
When Wyatt and Josephine are riding together, her right leg over the horn of the sidesaddle is obviously a prop. This can be verified after she gets to the bottom of the hill and turns her horse to the right. Her real leg can clearly be seen hanging on the right side of the saddle as she rides away.
When Wyatt and the others leave two cowboys hanging in front of the Dragoon Saloon, you can see clearly that neither man actually has a rope on his neck. As the one man swings around, on his jacket you can see the outline of the rope going straight down into the harness that's holding him.
In the O.K. Corral scene, the last Cowboy is simultaneously shot in the heart and through the head by Doc and Morgan respectively. When the shot cuts to him lying on the ground, he is visibly breathing.
When Curly Bill is confronted by Marshall White, Bill shoots him with the gun in his right hand as he is swinging the weapon up. Before the gun goes off however, a bright light that is supposed to be the muzzle flash can be clearly seen to come from somewhere near the ground and not from the muzzle of the gun itself. Also, after White has been shot, a large amount of smoke can be seen shooting back out of the area where the bullet was to have struck him, probably from the explosive charge used to set off the blood pack under his shirt.
The goof items below may give away important plot points.
When Virgil returns to the Oriental after being shot, Wyatt and Morgan's meal includes broccoli which was practically unknown in the United States until the 1920s when it began to be commercially cultivated in California.
When Virgil, Wyatt, and Morgan are playing pool after Marshall White is shot, Virgil and Morgan are wearing their guns and gun belts. However, when Virgil steps outside and hears the gunshots he reaches for his gun and it's not there.
When the Earp posse is pursuing the Cowboys after the death of Johnny Ringo, there is one scene that features five riders in the Earp posse, whereas there should only be four as McMasters was killed before this.
Towards the end of Earp Vendetta Run, when they have caught Behan and Ike Clanton, we see the four men riding in bright daylight. At the 1:53 mark in the film, it shows five riders at late sunset then switches back to four riders in daylight again as they chase down Clanton.
When Wyatt comes to visit Doc in the hospital at the end, Doc's eyes switch from being open and obviously awake to closed and almost seeming to be dead already between shots. Also, his head position changes.
As Marshall White steps up to Curly Bill, prior to Curly Bill shooting him, a wire is clearly visible emerging from his pant leg and trailing off camera. Presumably this is for the upcoming "shot in the chest" special effects.
In reality, Fred White did not die the night he was shot. In fact, it was his testimony that the shooting was accidental that led to the freeing of "Curly" Bill, not a "lack of witnesses" as shown in the film. He died two days after he was shot.
When Wyatt Earp kills Stilwell at the train station, Doc Holliday, Turkey Creek Jack Johnson, Sherman McMasters and Texas Jack Vermillion appear from out of the smoke. Vermillion did not join in the Earp Vendetta Ride until a day after Stilwell was killed.
Wyatt holds off a small mob wanting to lynch Curly Bill for shooting Sheriff White. One must assume they witnessed the shooting since they came up so quickly. Later, Wyatt complains that Judge Spicer dismissed the case due to lack of witnesses. It is possible (within the film, as the whole scene is not historically accurate) that the witnesses refused to testify for fear of Cowboy retaliation.
When Morgan dies his eyes are wide open. As Wyatt lays him down rolling his head to the side Morgan's eyes continue to focus at the ceiling instead of turning with the motion of his head as dead eyes would do.