I have now read a couple of reviews saying that it's not particularly gory, Nakahara.  I don't think I agree.  It's kind of what you would expect of a film set in WW1 trenches.  Lots of dead bodies and some shots of dismemberment/traumatic injury.  The story involves taking a message across a battlefield, and so there's less direct violence but a lot of seeing the consequences of it.  Maybe if you're able to look away at certain parts, it would be OK. 

Thanks for the heads up about the documentary, BB!

Gore-wise, I'm not sure - I don't remember much gore in Dunkirk, but it's a while since I've seen it.

I'm surprised that I preferred this to Dunkirk, although that may be partly because I've just seen it!  I think this feels smaller scale and maybe more personal than Dunkirk, as you're following the story of a couple of men delivering a message.  Everyone else is temporary and peripheral.  It felt very real at times, maybe partly due to those long shots, but also sometimes felt kind of magical and allegorical.  There certainly seemed to be quite a bit of religious imagery which doesn't seem to have been commented on in the reviews I've read, but I don't think can have been accidental!   1917 is sometimes very intense, but at other times calm and thoughtful.  I think the story is a lot simpler than Dunkirk, and having it happen in real time, more or less, simplifies it even further, so I found it a lot easier to follow.