When Marisol's family is freed, they walk away in the same direction as the Rojos that come riding into the scene a few moments later.

When Chico is left alone to guard the Rojos' compound while the Rojos are fighting the Baxters, Chico is shown riding on horseback among the Rojos gang when they are riding back to the compound.

When the large barrel rolls down the ramp, it is on two large rails. Right afterwards, Joe crawls down the ramp, and no rails are visible. The large rails reappear when his captors come into the room right after he exits.

After getting shot in the climax, the position of Ramon's body and his rifle changes between shots.

When Ramon and his men are killing the Baxter men running from the house fire, Ramon has 9-10 men. Yet, in the final gun battle, there's a total of only 6: five men on the street and one above.

When the Rojo gang ambush the Mexican army unit the gun Ramon uses to kill all the troops is a Mitrailleuse volley gun. Each barrel had to be laboriously loaded by hand before all barrels were fired together in a single volley. However, the film shows the volley gun being used as a form of machine gun. The only machine gun around at the time was the hand-cranked Gatling gun which the soundtrack also seems to depict.

A volley gun could fire each round individually using a hand crank. However, Ramon clearly has both hands on the (incorrect) twin grips at all times.

Although there was smuggling at the border between Mexico and the U.S., Silvanito is wrong when he says that alcohol and guns cost much less south of the border. Alcohol was very heavily taxed in Mexico. Guns, being manufactured in the US, were similarly more expensive. Therefore, smugglers purchased goods north of the border to sell them illegally in Mexico.

Mules have long ears, no hair at the base of the tail, and low withers. Joe's mount has short ears, hair on the whole tail and normal withers; i.e., it's not a mule but a horse.

Joe cuts his bulletproof breastplate out of the middle of what appears to be a boiler. It would have been impossible for him to have done this with just the hand tools he had at his disposal.

The Mitrailleuse volley gun shown at the riverside ambush scene has several dozen individual barrels that could each fire just one shot; the weapon is not a belt-fed repeater-cannon like a more-modern machine gun. Yet literally hundreds of shots are seen and heard to be fired in this scene.

Obvious horse riding double for Clint Eastwood during the entire sequence where he rides back to town while trying to avoid the Rojos.

When the Baxters and Rojos exchange prisoners and Marisol begins to move forward on her horse, there is a window in the background that reveals there is no back wall to the building; the distant landscape can be seen through it.

When Joe escapes the wine cellar after his brutal beating, after he sets off the rolling barrel down the ramp to take out Chico and the other baddie, a special effects wire can be seen on the right side of the barrel half way down the ramp that presumably sets of the exploding barrel effect when it hits the closed door.

Obvious day for night shots during the graveyard shootout.

When Joe is target practicing at the party and Ramon starts shooting a Winchester rifle at a suit of armor, it can be seen that the holes were pre-punched into the armor.

Joe walks into a room with five bad guys and starts shooting. Only four gunshots are heard, but when the smoke clears, all five baddies are down.

When the Baxters and the Rojos are shooting at each other at the cemetery, Ramón Rojos runs over the tops of the rocks to get a better shot. As the Baxters fire at him, there is one bullet that hits the rocks under Ramón that had no sound of a rifle being fired nor any ricochet sound.

At the end, when Silvanito shoots Esteban Rojo, the sound of the rifle being fired is heard, but Silvanito is not actually pulling the trigger.

The machine-gunner is shown to be "vibrating" with the staccato-discharging of his weapon, yet his bodily shaking continues even in between intervals of firing the cannon.

While the hero is preparing his custom bulletproof vest, the sound of the rasp doesn't match his movements.

When 'Joe' is riding towards the small house along the valley floor there are tyre tracks visible in the dust.

In one scene showing the hills beyond the town, the ruins of Tabernas Castle can be seen on the hilltop, showing that it was filmed in Andalucia, Spain. The castle was used by Fernando and Isabella during their siege of Almeria in the 1480s.

In all the desert scenes, there are no cacti visible. Cacti are found only in North and South America, making it obvious that this was filmed in the Old World; in this case, Spain.

The explosion at the front of the Baxter's house causes minimal damage and the fire doesn't even touch the house, simply burns outside.

However, the entire family and Baxter' s men choose to run through the front door into the fire and hail of bullets, instead of exiting through the more obvious rear of the house.

During the shootout in the cemetery, Ramón shoots the (dead) soldiers on the tombstone. As the (dead) soldiers don't move or react at any time during the shootout, wouldn't that indicate that the soldiers weren't alive? Yet no one in the shootout seems to notice.

When Joe goes to rescue Marisol he shoots her captors. Within seconds the Rojos run out of their house and one of them states the shooting came from the small house. The next few scenes show the Rojos and Joe riding at full gallop for several minutes between the two houses, indicating there must be a considerable distance between them.

A horse can run at more than 35 miles an hour, so around three to five miles in 5 to 10 minutes. Even if the Rojos could have heard the gunshots this many miles away from inside the house (plus the shooting was inside a house too), they certainly wouldn't be able to tell where they came from. They must constantly be racing to and from the house every time they hear a gun going off in the distance, day or night.

The coffin maker makes numerous coffins for various characters throughout the movie, however, it is never made clear who pays for the coffins or who pays the man himself.

If Marisol is hiding at the Baxter's house, as is assumed, it doesn't make sense to set fire at that house.

When the Baxters and Rojos are in the street for the prisoner exchange, there's a close-up of Ramon cocking his rifle, but the hammer is already cocked.

In the final shootout with Ramon, Joe loads only one bullet in his revolver, then quickly spins the cylinder. This would have given him only one chance in 6 that the cartridge would be under the hammer when he pulled the trigger. One experienced gunfighter would have caused the cylinder to click only four times. With practice this can be easily and quickly accomplished by dragging the cylinder from the base of the middle finger to the fingertip (with small changes to allow for differences in the size of the hand).

When Joe first arrives in town, Silvanito tells him that the coffin-maker can get anyone's measurements with just one look. Yet in the final scene he can be seen using a measuring string with the dead Rojos.

The Man With No Name never says his name, only the Undertaker calls him by the slang term Joe.