[The] movies have rarely tried to look at modern Ireland with modern eyes, in spite of the riches of dramatic material to be found there….

Which is one reason The Informer comes with such novelty and vitality. Another is that Liam O'Flaherty's novels have little in them of the stuff from which ordinary movies are made…. His books would be a stiff dose for the ordinary audience if they were put on the screen in the key he wrote them in.

Dudley Nichols and John Ford have struck a somewhat gentler strain from the harp of old Erin. One with his scenario, the other with his directing, they have made of The Informer something that popular sympathy can more conventionally respond to. They have romanticized the motive for Gypo Nolan's turning informer, making him do it for a girl—as if hunger were not an effective enough reason. All the women in the story have been stereotyped into lay figures used to suggest the usual heart interests of commonplace fiction, and do not count very much. But these little compromises have left intact what is essential to the tragedy of a man who was the victim of his own character. (p. 8)

There is a grim splendor to it, both as a tragedy and as a motion picture. Fundamentally it is honest in intention and sincere in execution. The man's character is truly understood and truly portrayed, with the inevitability coming from its own nature that great tragedy always has to have. The film illustrates powerfully the old dictum that character is destiny….

The writer of the scenario dealt honestly and ably with the O'Flaherty character, and encompassed it in a framework that follows the best motion picture technique. John Ford has directed it with a fine eye for picture effect, both atmospherically and dramatically. Occasionally he slips into old movie ruts that seem outworn—fade-ins to supply deficiencies in the audience's imagination, for instance, that must seem quaint and unnecessary at best to any alert audience of today. But subtle and powerfully suggestive is the way he has paralleled the blind twistings of Gypo's inner nature with an exterior presentment of dark foggy streets peopled with dim figures and dimmer shadows, with the action erupting into some place of light and noise whenever Gypo emerges into positive activity….

Pictures like this come rarely, and it will make an interesting test of how justified people are who insist that audiences are eager for better films than producers provide. (p. 9)