Let's be realistic.

Good concept, poorly executed.

Instead, you get a movie that's enjoyable enough, but leaves you feeling like it could have been much, much more.

Just intense enough to provide a much-needed diversion, just lightweight enough to make you forget about it soon after it’s over. It’s not exactly “good,” per se, but it does what it sets out to do in terms of putting us on edge, which makes it … successful?