To my surprise, almost completely useless. The director cuts various "ordinary filmgoers" (from grannies who remember the '30s to the modern kids) talking about their film-going. These reminiscences are cut with bits of films, none of which are identified. Unless one has seen KANAL and EROICA there's no way to know what's what. If one has any desire to know about the history of Polish cinema, best steer clear.