Complex sentence: The post-airing success of the show led Whedon and Universal Pictures to produce "Serenity", a film based on the series, and the "Firefly" franchise expanded to other media, including comics and a role-playing game.
Split into simpler sentences: The post-airing success of the show led Whedon and Universal Pictures to produce "Serenity", a film based on the series. The "Firefly" franchise expanded from the series and film to other media, including comics and a role-playing game.