Factual error: The strong current of the river the main character falls into carries him to a considerable waterfall. There is not, nor has there ever been, a river of that kind in the Ecoust front line area, let alone a waterfall. Anyone who has any insight into the geography of the region will tell you it is flat as can be. The largest body of water, the Yzer, gently meanders and flows into the Channel, even during really rainy times.
Suggested correction: I do not believe that either Ecoust or Croisilles Wood is in Flanders. Both are behind the old German lines at the Somme. That said, there are no bodies of water in that area.
Ecoust and Croissilles are in department Pas-De-Calais in the French Flanders, together with the Belgian flanders they are called Flanders Fields. It is indeed a flat area.
Also, the message in ink delivered is legible, despite having been submerged in water. And don't get me started about the attack from ridiculous trenches and not a barbed wire in sight.
It's not. Even French Flanders is further north. But, even though there are some high points in the area, like Vimy Ridge that rises to about 500 feet above the surrounding plains, the slopes are quite gentle. And, as you say, wouldn't allow for the kind of drop seen in the movie.
There is a watercourse that goes through Croisilles... But it's basically a ditch.
Character mistake: Scene where they push the truck out of the mud; right after they drive away in the background you can see that the other side is flat grass. They never had to do all that.
Suggested correction: Trucks of that era were not equipped with limited slip, nor posi-traction differentials, so having their truck land in mud on the drive axle side of the differential resulted in exactly what's portrayed in the movie.
