Use of color
The primary image technique in this book is the clever use of color. By slowly removing certain colors from the book, the color itself becomes a kind of imagery, showing the slow descent into absolute panic and terror as the soldiers realize that this war is not like any other war in human history. They didn't have mustard gas, tanks, or machine guns in previous wars. The effect for the soldiers is that they can't believe their eyes, and for us, that is shown through the colorless, nightmarish depictions.
European life and culture
Before WWI, Europe was one way, and afterward, it was permanently different, and those changes remain until this day. WWI was so violent and disturbing in nature that an entire continent basically walked away from their traditions and religious beliefs. In light of the truth of human nature, European pleasantness was gone. This book depicts those things by showing what the world was like when the soldiers were sent off. The soldiers leave a version of their homelands that, by the time they come back, will be completely different.
Trench warfare
Trench warfare is the main topic for Tardi's depiction of WWI warfare, not surprisingly. It perfectly captures what the war was like in general, with both sides sustaining unbelievable casualties as they tried to adjust their expectations for what war would be like now. (Before this war, battles were fought completely differently; the trenches represent a pivot-point in human history). These depictions occur in both the drawn images (it is a graphic novel) and also in Tardi's writing.
Images of horror
The graphic novel tells of terrifying, gruesome forms of warfare that had not existed ever before in human history. The feeling is surreal and nightmarish, because of the darkness of the historical facts, but also because of the added layer of visual depictions. Many people know about WWI, but seeing images of what these weapons actually did to human bodies is an experience all its own.
