I can’t recall the last time one movie made every person in the theater jump at the same time; I mean every single person. Most horror movies make a few girls scream but most just turn their heads to the side and try not to look. This is not the case in Shutter Island; the film is so compelling that you are forced to watch and when the moment to jump arrives there is no way around it: you jump.
Part of the film’s success derives from the experience of the people involved. There is no doubt that Martin Scorsese is one of the greatest directors Hollywood has conceived. You might think Shutter Island is not a typical Martin Scorsese film, after all he is usually associated with gangster movies: The Departed, Gangs of New York, Casino, Goodfellas, Mean Streets, etc. But he has his share of horror films: After Hours, Cape Fear. And in most of his films he has one (or more) of his characters diving into insanity, most noticeably: Travis in Taxi Driver, Hughes in The Aviator, and one could make a solid argument for Christ in The Last Temptation of Christ. The point being Scorsese made the right choice by choosing to adapt Denis Lehane’s novel to the big screen. But a Scorsese film is not just made by Scorsese; Robert Richardson and Thelma Schoonmaker deserved their respective credits for the beautiful photography and masterful editing. Richardson has worked with Scorsese since Casino (and is also responsible for the photography in Inglourious Basterds) while Schoonmaker has been with Scorsese since the beginning. It would have been really hard for these three (four if we include DiCaprio in the mix) to F things up. By now they should be able to pull masterpieces with their eyes closed any day.
I could go on and on about the film’s plot and characters and the acting, etc. But for a movie with as many turns as this it seems irrelevant and I might give juicy details away accidentally. So instead I will simply recommend that you watch Shutter Island if you want a good thrill. Take your girlfriend; it would be perfect. The only reason I am not giving Shutter Island a 5 is because when placed next to some of Scorsese’s best it is not quite there.