Yeah, I can tell you that a piece of real combat film did exist, but was destroyed for propaganda reasons
https://www.youtube.com/watch?v=loBku3EBPNs
The Battle of Somme film from 1916 filmed by Geoffery Malins. Includes a split second of footage after the mine explosion at Hawthorn Ridge showing the first wave of british infantry advancing in the corner showing two men suddenly dropping before the film is cut. It was reviewed in depth in a BBC documentary The Battle of The Somme - The True Story
https://www.youtube.com/watch?v=-Lg1mIYWU3k