The gameplay in Clannad follows a branching plot line which offers pre-determined scenarios with courses of interaction, and focuses on the appeal of the five female main characters by the player character. The game ranked as the best-selling PC game sold in Japan for the time of its release, and charted in the national top 50 several more times afterwards. Key went on to produce an adult spin-off titled Tomoyo after ~It's a Wonderful Life~ in November 2005, which expanded on the scenario of Tomoyo Sakagami, one of the five heroines from Clannad.
Clannad has made several transitions to other media. There have been four manga series: the first serialized in Comic Rush, the second in Comi Digi +, the third in Dengeki G's Magazine and Dengeki G's Festival! Comic, and the fourth in Dragon Age Pure. Comic anthologies, light novels and art books were also published, as were audio dramas and several albums of music. An animated film by Toei Animation was released on September 15, 2007, followed by two anime series including two original video animation (OVA) episodes by Kyoto Animation. Both anime series and their accompanying OVAs are licensed by Sentai Filmworks and are localized and distributed in English by Section23 Films. The two Clannad anime series were released in North America in 2009. The animated adaptations have received high sales figures in Japan as well as critical acclaim abroad.