The Jack Reacher of Lee Child’s novels is a massive 6’5” bruiser. The Jack Reacher of cinema is Tom Cruise, who’s only about 5’7. But there’s something satisfying about this casting. You expect a giant hulk to be able to handle himself in a fight. Cruise’s Reacher is an underdog every time he wanders into a fight and then takes them down three, four, or five dudes at a time. Is it plausible that a 54-year-old vagrant could maintain a flawless physique and dominate packs of professional killers even when cornered and heavily outnumbered? Probably not. Is it plausible that a kid who gets bit by a spider could turn into Spider-Man? There are things a viewer simply accepts because it is the premise of the movie.