Most war movies are considered to be, by nature, anti-war. Lu Chuan's "City of Life and Death" feels more anti-human, as its balanced depiction of the Nanking Massacre is so dauntingly depressing that I almost don't want to recommend it. Were it not also a remarkable technical achievement of epic filmmaking, I might actually dissuade you. But, I mean, more blockbusterized tragedies like "Pearl Harbor" and "Titanic" are also marvels of craftsmanship, in their own digitally spectacle-ized ways (this is not to say they're great movies as a result). And "City" doesn't shy away from action sequences as thrilling/harrowing as parts of "Saving Private Ryan." However, this film doesn't romanticize so much, or really at all, and while it has minor elements of hopefulness in the end -- thematically you might be surprised it doesn't end with a montage of subsequent holocausts, genocides and atomic bombs dropping (something akin to the terrible bit concluding "The Way Back," for instance) -- I think this quote from Lu from the film's production notes speak to what you can expect with his film's tone:
"I found the basic truth that a massacre is not the special talent of the Japanese people. It's a talent of human beings, you know? All kinds of people kill all kinds of people. That devil is always in everyone's heart, so as human beings we need to be very careful."