The single-shot filming style provides a consistent and accurate spatial gauge of the physical setting in the movie, demonstrating the vast scale of no man's land and the distance that the characters are traveling to those that are curious and conscious about details like this. If anyone has the time and motivation, they could easily map out a 3D recreation of the movie to make a closer recap of events and locations.
Schofield's uniform serves as a good indicator of his mental state. At the start, he's in full kit and somewhat chatty but irritable. By the time he loses his helmet and rifle, Schofield's panicked and terrified. After losing his webbing and is down to just his basic uniform, Schofield breaks down sobbing before dazedly stumbling towards a group of soldiers and barely able to speak.
In an early scene, General Erinmore quotes from the Kipling poem "The Winners". The poem advocates selfishness; specifically taking credit for other peoples' work, or accepting help from friends and then refusing to acknowledge that help. The rest of the movie is a deliberate refutation of the poem's theme.
In contrast to the British trenches which were poorly constructed, the German trenches were in a much better condition because the Germans anticipated the war was going to last a long time and they actually made an effort on making their trenches comfortable as possible to the point of having underground bunkers and even electricity in some parts. Although this is also due to the fact the British regularly rotated units out of the line The British had a system where battalions were rotated constantly, so soldiers would spend a maximum of two or three days on the front line before going back to the support or reserve lines, and then on to rest.
The German trenches being abandoned was because they moved further to the Hindenburg line in April 1917.
The title of the track during the No Man's Land scene is "Gehenna". While Gehenna means "hell", which no man's land resembles, Gehenna was initially where some of the kings of Judah sacrificed their children by fire according to the Bible, just like leaders of Germany and Britain sacrificing their own youth in the fires of war.
The reason soldiers are seen sitting about at the start of the film is because there was actually very little action in trench warfare. On average soldiers on the western front spent most of their time being on standby, cleaning the trenches, catching sleep or writing letters because it was simply easier to defend than to attack.
Just before the first wave of the Devons go ‘over the top’ many of the soldiers are seen smoking cigarettes. The soldiers aren’t just smoking to calm their nerves but they know they may never come back alive and literally have a last smoke before being killed.
Although he doesn’t seem to have it at first glance, Scholfield already has post traumatic stress disorder or ‘shell shock’ as it was known back then. Schofield is a veteran having experienced the horrors of the Somme. As such he develops minor symptoms which worsen as the film progresses. He starts off as sounding nervous and cautious during the first half of the journey to the Devons. Him acting angry towards Blake after being nearly killed and temporarily blinded is him taking his stress out on Blake as it is obvious he didn’t want to take part in another dangerous mission. Then after losing Blake he becomes more unstable to the point he screams in panic when a truck carrying other soldiers is stuck in the mud. Then after he escapes a German solider trying to shoot him, he nearly drowns in a whirl pool and waterfall and he breaks down completely. But even when he pulls himself together to stop the Devons attacking, he again shows signs of distress. And it is implied by the end of the movie Schofield is left permanently scarred emotionally and will never regain his composure having wasted too much horrors and scares of the First World War.
Judging how Blake never fought in the Somme and doesn't understand the idea of why being on leave is sad as they eventually have to go back and fight, and the implication Blake is single, it is likely Blake was conscripted which came into force in 1916 while it is implied Schofield joined in 1914.
The French town in ruins is due to the Germans destroying it. Germany throughout the war tried various efforts to get to Paris, including invading the French fortress town of Verdun and didn't hesitate to destroy any town or city in their wake as long as it means getting to Paris.
Near the end of the film, a captain is seen crying. At first glance it might be because he does not want to fight but it is actually shell shock, now known as post trauma distress. As the war went on many soldiers lost their sanity due to the number of deaths, the dangers and trench conditions and the fact they could die or get wounded any second of the day. And to make it worse those who had it were likely executed for not cooperating rather than being diagnosed with it as it was not thought to be a mental illness in those days.
During the climax we see lots of British soldiers 'going over the top' towards the German trenches. Seeing this gives you a rough idea on what it was like in real life especially as most of the soldiers who left the trenches never came back either by death or taken prisoner. And most if not all the soldiers knew their chances of survival were very slim.
As well as tear jerking, seeing Colonel MacKenzie's soldiers being seriously wounded can send chills down your spine when you realise not only are their injuries very gruesome but also the fact there was no proper medical treatment that we have today. If you listen very carefully one of the first aiders says a solider needs to go straight to surgery to get his leg amputated. That part can be more chilling if you watched the film Gone with the Wind where a doctor tells an injured solder the same thing.
After being stabbed to death by a German pilot, Blake is simply abandoned by Scholfield as a strict order. Considering Scholfield and the others leave the scene it could be implied Blake’s body will simply decay into a skeleton or be feasted on by rats. Same with the deceased German pilot. This could apply as fridge brilliance because nowhere was safe to dispose of the bodies due to an ongoing war where people can get killed anywhere.
While crossing no man's land, Scholfield first cuts his hand on barbed wire, then accidentally sticks it into a decaying corpse before the bleeding has even stopped. Then he gets shot for good measure. He's probably got a nasty infection, he's in a warzone, and antibiotics are still in their infancy. Even if the Germans don't get him, he'll probably, at best, need his hand amputated.
Even worse than his other injuries, he is knocked backwards, hits his head, and loses consciousness for quite some time. In addition to being concussed he might very well have a brain bleed. In today’s modern medicine you would require a ct-scan of your head, as well as close monitoring for at least 12 hours, if you’re knocked unconscious for even a few minutes. Schofield is unconscious for several hours, which is quite alarming.
While she is hiding, there is a strong possibility the young French woman will eventually get captured by the Germans along with her adopted baby. And it is likely if she does, she will likely get executed. And to double the horror, it is heavily implied her friends & family have been captured and or killed and that her village was just recently destroyed by the Germans.
While not exactly horrifying, Blake and Schofield might at first glance be all alone between their own trenches and where Blake gets killed, but there was every single chance both men could get killed by the Germans. If any German had seen them, they would kill them on the spot. Likewise if Schofield & Blake encounterd any Germans near their trenches then they would have to kill them too, to protect not only themselves but their fellow comrades.
