My great uncle fought in this war. My grandfather told me about how his uncle had been exposed to gas and had lingering damage from it. Seeing this movie and how the battles were fought really put into perspective the things he had to deal with.
The movie has some differences from the book which is ok. It doesn't take away from the message at all. I've seen some comments talking about how it's "Nazi propaganda" however that would be furthest from the truth. The whole point of the book was to describe the absolute horrors these people faced in battle, at home, and the psychological effects of it all. The book doesn't glorify anything and neither does this movie. In fact the characters receive a wakeup call immediately upon entering the trenches. They realize they're now stuck there and all they can do is survive. Battle isn't glorious, it's straight up kill or be killed. Fight till you cannot fight anymore and hope one day there will be peace.
This is worth the watch.