The Spanish Prisoner

I love movies that make me think about them afterwards, especially the puzzle-like ones such as Memento and the best Hitchcocks. Such movies are rare gems these days, when entire websites are devoted to movie mistakes.
In this genre, "The Spanish Prisoner" by David Mamet is a real treat. Like most good thrillers, it has a lot of plot twists and unexpected surprises, but nothing out of the ordinary. In fact, the plot seems disjointed at times, and seasoned viewers of these movies might find mistakes. To see if I 'got it', I went to IMDb and checked out the user comments. Most reviewers found it a so-so thriller, ok in its genre. But one reviewer remarked mysteriously that 'almost no-one really understands this movie'. Intrigued, I went looking for more info and found a site that attempts to explain it all. Warning: I strongly advise against visiting this site if you haven't seen the movie.
To me, it shows courage for a director to make a movie that almost no-one understands. Ridley Scott (possibly inadvertently) did the same with Blade Runner, a movie with a secret that is never explicitly revealed. But there, the dazzling visuals and intriguing main story line greatly helped the movie. In Mamet's case, the viewer must dig deeper to appreciate the hidden gem.