As in most of the films made about WWII before 1946, the
German helmets are WWI vintage. They look somewhat similar. This movie, however, being made in 1942-43 would make it very difficult to obtain German WWII helmets.
In the scene when the Italian POW is helping work on the tank, Bogart's character is tightening a nut with an adjustable wrench (Cresent). The camera angle shifts to another view of the scene and he is tightening the same nut with a non-adjustable wrench. The camera angle shifts back to the original view, the Sergeant is again using the adjustable wrench.
In the opening scene. Sgt. Gunn can be seen working on a tank with its front end pitched up because it is sitting in a ditch. Moments later this tank is shown exploding, but the tank is flat on the ground when the shell hits. Then the tank is shown sitting pitched up in the ditch again.
There are two flags flying on the tank Lulubelle. In the opening scene, the lower flag is shown as artificially erect (like the US flags on the moon), only to be shown moments later fully flapping in the wind.
The lower flag flying from Lulubelle is inconsistent in size and color throughout the film. In the opening scene the lower flag is completely white and only slightly larger than the top flag. As the tank departs the opening battle the lower flag is more than twice the size of the top flag. Later in the film the lower flag is two-toned with a dark circle in the lower half.
The dog tags held by Gunn at the end are inaccurate. British soldiers wore two dog tags - one circular and one octagonal. These were not made of metal. The circular one was attached to the cord through a hole in the circle, not through an additional loop. The soldier's religious affiliation was shown on the tag as well.
Tobruk fell on June 21st 1942, which places the action just after that time. At the end, when it is said the British held the Germans at El Alamein, this time-frame for the movie becomes distorted. The First Battle of El Alamein lasted from the 1st to the 27th of July. This group of soldiers has not been in the desert for that long.
When Bogart is giving instructions to Waco before he leaves to get help, he says they're trying to hold up a battalion. In the German army (and many armies for that matter) a battalion is 1000 men. So, this would be about a half a battalion.
One of the machine guns shown is an M1917A1 Browning belt fed, water cooled machine gun. The gun has an eight pint cooling system that is recycled via hose to a reservoir. In this film there is no hose or reservoir visible; even though the gun is fired at length.
In the last few minutes of the movie where MSgt Gunn and the other soldier comment that the last German shell was a direct hit on the well, there is an insect crawling on the camera lens in the lower left corner.
When Tambul and Giuseppe first approach the American tank from a long distance away in the desert, they are being observed from the tank through binoculars. As they get closer, their images in the binoculars are looking to the side of the observer, instead of directly at him, and they walk past the observer and the binoculars, even though they are still very far from reaching the tank.