Someone who complains about "lack of depth" doesn't get it. This is a very well-acted--in fact brilliantly acted--well-directed, well-paced, well-plotted thriller. If you want "depth", see subtle films about love and betrayal and friendship, etc. Nothing wrong with that, but this is a thriller. We know enough about the characters to make us care, and man, we do care! and make them believable. That's quite enough for a thriller.
As others have observed, the actors are magnificent. First, the unwilling hero: as in great Hitchcock films (I'm thinking particularly of "North by Northwest"), he's an ordinary guy, not a tough, trained super-hero. Gilles Lelouche is totally convincing in that role. And the one who seems to be the bad guy, Roshdy Zem, and who develops in the course of the film, is perfect. Neither he nor anybody else in this film overacts.
As others have observed, the actors are magnificent. First, the unwilling hero: as in great Hitchcock films (I'm thinking particularly of "North by Northwest"), he's an ordinary guy, not a tough, trained super-hero. Gilles Lelouche is totally convincing in that role. And the one who seems to be the bad guy, Roshdy Zem, and who develops in the course of the film, is perfect. Neither he nor anybody else in this film overacts.