This seems to be Buster Keaton's most popular short film. I prefer his films with more cinematically based comedy, such as in "The Playhouse", "The Frozen North" and "Sherlock, Jr.", but "Cops" is a very entertaining little film. It features a large comedic chase--chases, especially involving policemen, being one of the most regularly reoccurring devices in Keaton's oeuvre, especially in his two-reelers. Cops chased Keaton in "Convict 13", "Neighbors", "Hard Luck", "The Goat" and--in an escalated chase very similar to that in "Cops"--"Daydreams". My favorite Keaton chase, by the way, is the chase of the brides in "Seven Chances".
The comedic chase has a long cinema tradition, perhaps dating back to James Williamson's "Stop Thief!" (1901) or "Chinese Laundry Scene" (1895), the latter of which was based on a vaudeville act. Then, there were the Pathé comedies and those of Mack Sennett's Keystone, which were greatly derived from them. Keaton came from vaudeville and worked under one of the premiere early comedians, Roscoe "Fatty" Arbuckle, to begin his on screen career, so he was fully immersed in this tradition.
In "Cops", there are some good visual jokes that rely on film technique, such as following a close shot of Keaton behind bars with a reverse long shot that clarifies the opening scene. Keaton's mechanical inventiveness is demonstrated during the horse carriage sequence. And, there's plenty of physical comedy during the great chase finale. Keaton's sense of matured, restrained comedy is also important here, which is perhaps best characterized by his retained stoic expression throughout any chaotic misadventure. "Cops" is rather representative of Keaton's refined sense of what's funny and of his advanced understanding of film-making.
