My one big problem with this (SPOILERS)
My one big problem with this was the casting of Pat Healy as the main character. At the beginning of the movie we see him as a normal family man, but as his need for the movie becomes more and more intense he's willing to do more of the things asked of him which results him him completely losing his mind.
The thing I didn't like was that he does an extremely good job of looking crazy, so it was too easily believable to see him become crazy at the end. I would've liked to see someone like Clark Gregg have been cast because I've never seen him play a crazy character, so I think it would have made the transition look a little bit more unexpected.
-Don't fall in love with somebody who dosn't love you back-