The singular thing about war movies is that no matter how accurate they try to be, they always forget something… or that they necessarily have to sanitize what happened because the truth would be unwatchable.
Sometimes it’s small details that get left out. You see soldiers with uniforms that are too clean, or hear an explosion that sounds too much like an old recording and doesn’t have the same nuance or depth of character.
Sometimes it’s big things. Soldiers get shot and fall in comically exaggerated convulsions, screaming and staggering and making a big spectacle. Or a scene set in 1915 will have steel helmets (If only we’d had those!), or the jargon will seem a little off, like they just poured over resources on trench slang and smattered it liberally with no regard to how we actually talked.
But the biggest difference between war movies and the actual experience is in the obvious: there’s always a level of detachment and unreality there. The nature of the medium won’t allow you to experience the horror fully. But also, if some director were somehow capable of using every psychological trick to pull you in as effectively as possible, the film would be so intense that grown men would leave the cinema in tears and shaking.
Even the actual battle footage can’t fully convey the horrors. You certainly can’t hear the din of constant shell fire, or the frantic yells of sergeants barking out orders (their voices were the loudest; the dying were astonishingly quiet as I recall), and you can’t really see the rotten pools of red kicked up by so many explosions. Many of the films of the day, such as the footage from the Battle of the Somme, were actually re-enactments performed by soldiers under controlled circumstances; that’s why they look so calm and confident. You know the real footage by the looks on the men’s faces, from wide-eyed fear to forced gallows grins, but you can’t hear them complaining about the food or singing the songs that kept them going.
I have maybe a minute or two of actual memories from the trenches of the Western Front, but those two minutes or so loom large over my life because they carry a lifetime of intensity. They were seared white-hot into my being and are still with me.
I have yet to find a movie that really shows the war as intense as I remember it, and I don’t think I want to.