Moore used the story as a means to reflect contemporary anxieties and to deconstruct and parody the superhero concept. Watchmen depicts an alternate history where superheroes emerged in the 1940s and 1960s and their presence changed history so that the United States won the Vietnam War and the Watergate break-in was never exposed. In 1985, the country is edging toward World War III with the Soviet Union, freelance costumed vigilantes have been outlawed and most former superheroes are in retirement or working for the government. The story focuses on the personal development and moral struggles of the protagonists as an investigation into the murder of a government-sponsored superhero pulls them out of retirement.
Creatively, the focus of Watchmen is on its structure. Gibbons used a nine-panel grid layout throughout the series and added recurring symbols such as a blood-stained smiley face. All but the last issue feature supplemental fictional documents that add to the series' backstory, and the narrative is intertwined with that of another story, an in-story pirate comic titled Tales of the Black Freighter, which one of the characters reads. Structured at times as a nonlinear narrative, the story skips through space, time and plot. In the same manner, entire scenes and dialogue have parallels with others through synchronicity, coincidence and repeated imagery.
A commercial success, Watchmen has received critical acclaim both in the comics and mainstream press, and is considered by several critics and reviewers to be one of the most significant works of 20th-century literature. Watchmen was recognized in Time's List of the 100 Best Novels as one of the best English language novels published since 1923. The BBC described it as "The moment comic books grew up."
After a number of attempts to adapt the series into a feature film, director Zack Snyder's Watchmen was released in 2009. A video game series, Watchmen: The End Is Nigh, was released in the same year to coincide with the film's release.