It's more of a mystery-psychological-thriller. It has some great actors like Leonardo DiCaprio, Sir Ben Kingsley, and Max Von Sydow. And they all pull their weight with some great performances. The biggest drawback I guess is the mystery part of the story. I don't like figuring stuff out. I don't often try to figure out what's going on in a movie. I prefer to let the story unfold as it was meant to, and be surprised at the end. I like to leave the problem-solving part of my brain shut off as best as I can. Sadly, I figured this one out about half way through. But even that isn't the drawback. It's when I watch a movie where it's all about what's really going on, once you figure out the big secret it's less appealing to me to watch it again.

A good comparison may be a movie that I love: Fight Club. There's a twist at the end of the movie, but that's not what the movie hinges on. So even when I know about the twist the movie is still so enjoyable to watch again.

That's not to say that Shutter Island is a bad movie. It's a very good movie... the first time. And it may be worth another viewing to try an catch some hints and things you missed on the initial viewing. I'd recommend seeing it, but I'm not dying to watch it again.