Call this film's flaws Legion, for they are many. Yet somehow it still kind of works. Despite a formulaic plot that falls apart under any sort of serious consideration, absolutely wooden performances from most of the cast, and the fact that there's exactly one likable character in the entire movie, Scott Stewart's Legion still serves up enough scares to be worth the price of admission.
At it's core, Legion is a by the numbers siege flick. An assortment of mismatched characters are trapped in an isolated location and must work together to save themselves from an overwhelming threat, it's a simple and serviceable plot framework that has served many movies before Legion and will likely serve many movies afterwards. Yet there's no shame in being formulaic, at least not as long as the formula is put to good use. The siege genre has stood the test of time because it's simple yet effective - it depends upon creating feelings of isolation and claustrophobia, and as such it's a perfect fit for horror films
Legion successfully creates the oppressive atmosphere that any good siege flick needs, but it undercuts itself by not making its threat seem really credible - the hordes of angel possessed people that assault the diner where the main cast holes up are too faceless and seemingly incompetent to inspire any sense of dread in the audience and Kevin Durand's Gabriel is entirely one-dimensional. One-dimensional is a word that could be used to describe most of the cast as a matter of fact, and that's a major flaw. It seems as though most of the characters are limited to one personality trait and one type of dialogue, begging the question why such talented actors as Dennis Quaid and Tyrese GIbson were required for such woefully underwritten roles. Paul Bettany's archangel Michael and Adrianne Palicki's Charlie are two of the worst written characters in the film, despite being central to the plot - they're uninteresting and simply unlikable, respectively. The one well-written and sympathetic character in the entire movie is Lucas Black's Jeep, and even he is relatively flat.
One thing that Legion definitely does not lack is effective scares. Every time the audience begins to relax, thinking that they've seen everything the film has to throw at them, they're proved wrong, and usually in the goriest manner possible. The ice cream truck scene is truly creepy to give just one example, as is the invasion of the diner by a possessed young child. Also, while it would be a stretch to say that Legion is a truly intelligent film it does raise some fairly interesting questions about faith and giving someone what they want versus what they need. Overall, Legion is a good but not great movie that should satisfy most horror fans as long as they don't think too much about it - just why was that one particular infant the key to humanity's survival, anyway?