From the Game's Introduction:
Retrospect is a story game inspired by made-for-TV documentaries detailing the rise and fall of rock bands - shows like Behind the Music and Biography. In it you play a member of a rock band that goes from playing sleazy dives and bars to festivals and arenas, and then, like many famous bands, burns out in a blaze of glory. Some of the band members will go on to lead ordinary lives, others will go down darker roads, and some may even pay the ultimate sacrifice. Anything is possible.
Like its name suggests, the game is played as a retrospective: The group will be telling the stories of the major events that shaped the rise and fall of your rock band. These stories can be comedic, dramatic, or even tragic - the best ones will demonstrate all of these qualities. As such it's much more of a collective story telling game than a traditional RPG because many of the scenes and narratives will take place as stories being told about things that happen in the past rather than in the here and now.
Retrospect is a GM-less game that can be played in one to two sessions: Some games will last only a couple of hours, others might take longer depending on how many players you have, how much depth the individual scenes go in to as well as whether or not your band implodes from internal or external forces. As a GM-less game it is a prep-less game - no prior preparation aside from some minor printing and cutting is needed.