In my western German view, it's a movie about a not very smart woman, with a talent for singing, surrounded by mostly not especially intelligent people, in a communist country where intelligentsia was either toeing the one-party-line or regarded with suspicion. Apart from a few easily recognizable and unrealistic propaganda statements, certainly necessary to help the film pass censorship, it's probably an honest depiction of the life of mediocre musicians in a country where art and culture where regulated by the state. It's also very boring, because there was no freedom to do interesting things and no such opportunities anyway, I guess. If you're not especially interested in life in the former GDR, stay away from this sad example of top-down imposed mediocrity or you will regret you wasted your time on this.
Review of Solo Sunny
