The C47's that are carrying the 101st Airborne supposedly have left around midnight. Yet when they are crossing the English Channel, it appears to be early dawn. When they are crossing over the coast of France, though, it becomes night again.
Early in the movie when Boyce is struggling to get loose from his parachute and swim the the surface of the lake he cuts the lines with his bayonet. As he swims to the surface there isn't anything in his hands, but when he gets to the surface he again has the bayonet and uses it to cut a hole in the parachute.
After the Americans first go to the attic, Corporal Ford's hair repeatedly changes shape between shots.
When the airborne trooper free falls 30 seconds before opening his parachute, he would have impacted the ground much sooner. D-day drops were made at 700 feet AGL, which didn't allow time for free fall and required the static line to deploy the parachute immediately. As reference, the first 10 seconds of free fall take ~1000 feet. The idea of dropping at lower altitudes is to not give enemy gunners much time to shoot paratroopers under canopy.
The only African-American airborne outfit was the 555th Parachute Infantry Battalion (Triple Nickels). Although the unit was ready for combat, it came close to being used in the Battle of the Bulge but that crisis passed and the unit never went overseas or saw combat.
A C-47 that lost its engine would have also lost its wing. The level flight shown the film would not have been possible without an engine.
The racial attitudes in the films reflect the 21st century, not 1944. Not only would African American soldiers not be in the White military units, many White soldiers at the time wouldn't even talk with or to them. Additionally, there would be a great more racial epithets spoken than were during the film.
When the squad is chasing Chloe through the woods, there are anti-tank obstacles, called 'Dragon's teeth'; these were used in open areas, not woods, to hinder tank movement.
01:01:05 Trench knives were double-edged and did not have a clipped point. The edge one this one is also facing the wrong direction.
One of the soldiers uses the term klicks for kilometer. Klicks was not used during WW2 and was not a common term until the Viet Nam War.
During the credits, a mock 1940s newsreel shows a United States flag with 50 stars when Jovan Adepo is credited as Boyce. The flag had only 48 stars from 1912 until 1959.
Soldiers of African heritage were not integrated with Caucasian units during World War II. This did not happen until July 26, 1948 when President Harry S. Truman signed Executive Order 9981, ending segregation in the armed forces, and not fully enforced until Secretary of Defense Robert S. McNamara issued Directive 5120.36 fifteen years later on July 26, 1963.
Corporal Ford's long hair and facial hair would not have been permitted in the US Army. His hair was even too long to be in style in the 1940s.
The flashlights used by the soldiers are of the correct design but the bright white light indicates they are using modern LED's instead of incandescent lamps. Period incandescent flashlights have a distinct yellow tint and are not bright by modern standards.
At 1:20h into the movie, we see the German radio room in detail. All the radio equipment visible there is indeed of WWII vintage. But the problem is - NONE of it is German, it is of American and British manufacture. What we can see on those shelves: AN RCA AR-88 receiver (USA); a Collins Navy TCS-12 receiver (USA); a National HRO receiver (USA) and a British R-1155 receiver, the latter used only in Lancaster bomber aircraft.
Flying from an RAF airfield in Eastern England would not take 90 minutes to get to their drop zone in France. Twenty minutes at the most.
When the zombie grabs Chloe and her brother tries to help her, she says "Go" to him in English although both are French and the brother never spoke English in the movie.
The troopers have just landed behind enemy lines and they are chatting with and shouting at each other. suicidal. shut up and maintain your interval.