I can't imagine anyone who doesn't know the original Pied Piper Story, but just in case: The city of Hamlin hires The Pied Piper to lead the rats out of city, but then they refuse to pay him. To exact his revenge, The Piper leads all of their children out of city and they are never seen again. This would be a very short movie if only that plot was used, so the makers of The Pied Piper padded out the tale to include stories concerning a traveling troupe of entertainers, an arranged marriage, and a Jewish alchemist and his assistant.
The costuming of the characters and the German location shooting were both good, but that's about it. Most of the movie was shot in wide shots, which to me is always distracting. On top of everything, the movie had the pacing of those dreary historical movies they sometimes showed you in school....you know the type....you would be all excited about watching a movie instead of having class, then find yourself watching a film which eventually put you to sleep.
I've always liked Donovan and his laid back flower power groove, so when I saw he was the titular character in The Pied Piper, I was expecting a movie with the same sort of vibe. Instead I got pounded over the head with ponderous statements about over-taxation, religion, hypocrisy, superstition and probably some other things that I have excised from my brain. It was disappointing to find that Donovan was only a minor character in the story and although he composed all of the music for the soundtrack he only sings three songs: "Riding Homeward", "People Call Me The Pied Piper", and "What A Waste of Time" - the last song perfectly describes this movie. The only people I can think who would enjoy The Pied Piper are those interested in seeing people wear funny hats (see below)
I couldn't find a trailer for the movie, but you can watch the whole movie in parts on youtube. Below is Donovan from a 1972 BBC appearance singing a song he wrote for the movie that didn't make the final cut.