Shutter Island is a 2010 film directed by Martin Scorsese, based on the book by Dennis Lehane. The film stars Leonardo DiCaprio, Mark Ruffalo, Ben Kingsley, and Michelle Williams. It is a psychological thriller where Leonardo DiCaprio, as Teddy Daniels, a US Marshall in 1954, travels with his partner Chuck Ale to Shutter Island. At the time, Shutter Island was a mental institution where the world's most criminally insane were housed. Teddy and his partner are sent to investigate the disappearance of a patient. As they continue their investigation, they stumble across disturbing secrets about the island, its staff, and the patients. 

The entire cast delivers strong performances throughout the film, with Leonardo DiCaprio's outstanding performance as Teddy Daniels. His portrayal of a confused yet determined character adds extra tension to the film. Mark Ruffalo also plays a pivotal role as Teddy's partner. The remaining supporting cast, including Ben Kingsley and Max von Sydow, provide a sense of unease and mystery throughout the twists and turns in the storyline.

Martin Scorsese creates a haunting and suspenseful atmosphere throughout the film. The dark, twisted setting of the mental institution, combined with the eerie cinematography and atmospheric music, contributes to a sense of unease and tension that keeps the audience engaged throughout the entirety of the film.

Shutter Island is most recognized for its excellence as a psychological thriller. The storyline does not fail to keep the audience guessing what's real and what is a delusion. The tension rises as Teddy discovers more of the island's secrets and delves into madness. The film raises complex questions about the nature of reality, guilt, and the human psyche.

The movie is best known for its unexpected plot twists. These twists add depth to the narrative, and they are a central part of what makes Shutter Island so engaging. Without giving away any spoilers, the film keeps viewers on their toes until the very end. Even after the credits, the movie keeps you guessing what really happened.

Overall, I rate Shutter Island 10/10. I personally hold Shutter Island in my top 10 movies list; however, some people may find the movie too dark or otherwise disturbing. It has one of the best endings out of any movie I have watched, and I would recommend every one of age to watch it.