Charlie is a boot camp private who has a dream of being a hero who goes on a daring mission behind enemy lines.
"Shoulder Arms" proved to be Chaplin's most popular film, critically and commercially, up to that point. This is understandable given the interesting themes and visual gags. The tree is pretty funny, and the underwater sleeping arrangements are amusing.
What I find particularly interesting about this film's success is how it seems to be now more or less forgotten. I mean, of course any Chaplin film or silent comedy fan will know it. But compared to "The Kid" or "Modern Times" or "City Lights", it is far removed... is this now even one of the top ten most popular Chaplin films?