Shutter Island

This film has one of my favorite plot twists that I've ever seen in a movie.  Shutter Island is an eerie story that opens your eyes to the life of the mentally insane, and makes you question where the line is drawn for treatment of those in mental asylums.  The movie features one of the greatest actors and one of the greatest directors of our generation with Leonardo DiCaprio and Martin Scorsese, and this duo did not disappoint.  Shutter Island is one of the most underrated movies of all time especially considering the hype other DiCaprio movies get such as Inception.  I was looking for reasons to not rate this film 5 stars and I failed to come up with one. Edit: I have realized there is in fact lots of hype around Shutter Island and it is thus not underrated.