Though slightly more accessible than 'Institute Benjamenta' (perhaps because Terry Gilliam was involved as executive producer), this is still heavy stuff -- what they call hermetic. Notions like fantastical, surrealistic and dreamlike just have to be taken more literally than usual to describe this film.
The story? A fairy tale really, but so bizarre it's hard to summarize. On a remote island, a sinister doctor controls events by means of a series of tide-driven automata (intricate machines comprising mini-worlds which control aspects of the real world). After murdering/abducting a young opera singer on the night before her wedding, the doctor calls in a piano tuner to do maintenance on his automata, preparing them for a cataclysmic opera in which he will wed the traumatized opera singer. Of course, the piano tuner falls for her and tries to prevent the doctor's plans...
Visually it is absolutely stunning. Partly animated, partly live action, the film is composed of rich tableaux shrouded in mystery and Mediterranean sunlight, which literally expose the machinations that lie behind the real (no: dream) world.
But the theme of puppetry is taken a bit too far, as the actors and the story all seem to be just instruments in this dream world. As one review puts it, the result, however beautiful, is just too stifling.
But maybe that's just another way of saying it's hermetic.