Legion is about the apocalypse and one fallen angel who tries to save the last hope for humanity. With such a high concept, it's weird how it's actually taking place in a rather constrained space : a truck diner lost in an American desert. My first impression was that the special effects looked cheap (witness the first human transformation and the way "it" talks while barely moving its mouth). It's an impression that stayed with me throughout until perhaps the final antagonist. My second impression was that the acting wasn't that bad. I didn't recognize the actor playing the main angel character (Paul Bettany) until the day after while reading the credits. He's not one we usually see as an action hero in this kind of flick but he gave a decent performance as the strong stoic type. I also remembered Lucas Black (playing Jeep : what a lousy character's name) from the time he was a talented child actor. He still is. We also have the ever reliable Dennis Quaid in a supernatural thriller yet again.
My third impression was that the little old lady (seen in previews) reminded me of the crazy old gypsy woman from "Drag me to Hell". It's no wonder she's shown in previews, it's one of the best moments. However it spoils the surprise. My fourth impression was that following the granny, the "possessed" people were rather slow, stupid and not particularly menacing, very much like zombies even though they were not. My fifth impression was that at least the filmmakers were trying to achieve character moments instead of tiring us out with incessant action. My sixth impression ,after the film, was that considering the origin of the possessed humans and the objective desired, it was really ridiculous and unbelievable to proceed that way especially considering the supposedly superior intelligence at work. My last impression is that although it's certainly watchable as a distraction, it's not really effective or a particularly good film in the genre despite the "angels", seldom seen in features these days. Don't watch "Legion" expecting a big-budget epic fantasy, it's more like an intimate, closed space, last stand b-movie thriller without that many thrills.
Rating: 5 out of 10 for mediocre
P.S. Don't watch it expecting a "legion" of "angels" either. You would be disappointed.