Well, not, that it is looking so bad, but: How do we know that this is set in WW I (other than from the title)?
I'm certainly no expert on war affairs, but did they really wear green battlesuits at that time ?
And did they have trenches within a town, only a half man's size deep and green on its flanks ?
And with ruins on both sides of the trench? Does that make military sense ?
I doubt it, I'm sorry to say
Lives of great men all remind us we may make our lives sublime