When you start watching this film you wonder if what you're going to see is worth and hour and a half or you are just going to know what happens 5 minutes later. Precisely, what makes this film a really recommendable one is the fact that there's a lot of twists and turns... Collet Serra shows you things to try and make you think... but your guesses seem incoherent when something else happens. So this in opinion of the popular viewers who want to enjoy going to the cinema, becomes the perfect movie to keep you on the edge of your seat; suffering because you try to understand but something does not match in the puzzle.
Of course a movie of such characteristics needs to sacrifice some things. Plus, you need to add that this is an american film from Hollywood. What this movie sacrifices is verisimilitude, especially at the end and in some parts. But I think that it is really important to sometimes do something unreal to make people enjoy the films... and this is what most of the movies end up doing. As said, this movie provides suspense, suffering (in a certain way), despair... a good film with a very good actor leading it, such as Liam. Just a few things to highlight as "not so good": the fact that Liam's character is an antihero, with all the circumstances in life against him and some things in the script that could have been more elaborated, such as the end.