“I’m not a nice human being.” By the time Peter Mullan’s Joseph admits this, we have more than enough evidence of our own eyes of his habit of unthinking, vile violence in response to any stressor, and directed toward absolutely anyone, down to the most innocent of transgressors on his temper. Joseph’s self-awareness is his tragedy, perhaps, and the triumph of writer-director Paddy Considine, actor turned first-time feature filmmaker, is that he makes Joseph a recognizable, even sympathetic human being while also giving us a brutal, bleak, and unrelenting look at his terrible deeds. (Considine, expanding on his multi-award-winning short film “Dog Altogether,” triumphs, too, with his powers of suggestion: the film is nowhere near as explicitly violent as your memory will immediately fill in, but he implies it so persuasively that you will be certain later that it’s bloodier than it is.) My quibble with the film isn’t that it’s harrowing or difficult to watch — films about violent men should be harrowing and difficult, not slam-bang entertaining — but that Considine is somewhat less generous toward the other side of his narrative equation: Hannah, the charity-shop worker and devoutly religious woman whom Joseph begrudgingly befriends. When Hannah is a mute victim of her abusive husband, James (Eddie Marsan), the film takes pity on her. When she strikes back against him, perhaps inspired, if subconsciously, by Joseph, Considine turns pitiless. As an examination of how different sorts of men — blue-collar Joseph and middle-class James — can be awful in different sorts of ways, Tyrannosaur is extraordinary. (The performances are riveting, too; Mullan [Boy A] and Marsan [Sherlock Holmes] are always fantastic, especially as not-nice human beings, but it’s Colman [Hot Fuzz], mostly known as a comic actress, who astonishes here.) Why the film chooses to dump additional cruelty atop a woman who is at the mercy of such men is a mystery.