What makes this particular cartoon great is that everyone watching it can empathize with Donald.
Donald portrays a WWII army soldier in training. He and his platoon go on a 40-plus mile hike.
He goes through all of the emotions which many of the GIs would have experienced. Even if you weren't a soldier, the idea of continually doing something until you're past exhaustion is something we can all relate to. It also shows the folks back home some of what training was like.
The animation, especially the backgrounds spoofing John Ford films, is beautifully done.
If you'd like to see more cartoons of this type, check out "Walt Disney on the Front Lines." This DVD collection includes over 30 short animation films. In addition, it includes the full-length feature "Victory through Air Power."