I like Jake Gyllenhaal as an actor a lot so I knew that I was going to like this movie regardless, but what I also got was a really good, tight thriller that I'd say definitely takes advantage of its clever concept. The train scenes are excellent - I love how he slowly pieces things together over the course of the movie -, but I think where the movie does fall apart are the real world segments as I think the direction that they take this part of the story, especially by the ending, did not really work for me. I was a bit disappointed whenever they switched back to these parts I guess you're not supposed to think too much about it and just enjoy the ride. It's only about 90 minutes but it feels ~10 minutes too long and the ending dragssss but it's still really fun and a very easy watch with some great direction/acting.