I first watched this movie right when it came out. At that time it was great and re-watching it took me back to those days. The movie captures the essence of the late 70's in Denmark and watching the movie in that perspective is certainly worthwhile. The clothes and hair-styles are unsurprisingly authentic, but so are the thoughts and emotions of the characters.
Steffen is an only teen-age child living with his mother, who smokes and drinks a little too much. He doesn't really know what to do with his life; he wants a job but not to any great degree. His days pass by with his attractive rich-family girlfriend until he meets Charly.
Charly is the odd-ball, happy-go-lucky character that tries to steal Steffens moped. They become unlikely friends and down the line, Steffen has to make choices between his girlfriend and Charly.
Apart from the setting, there are many aspects that are real to the 70's and aspects that are real to teenagers irrespective of which decade they live in.
On the bad side: I really don't think the acting is especially good. It was probably the best Denmark had to offer at that time, but by today's standards it falls noticeably short. The characters are superficial - the movie offers no insight to Steffens situation (how happy is he with his girlfriend? has he any realistic plans for the future? what is Charlys past? why did he end up at the institution?) There is very little character development. The movie ends but there is no climax or resolution of their problems.
So, with the good and the bad, the movie ends up with a "5" from me.