The moment I’ve told anyone this week that I watched I’m Still Here — Casey Affleck’s erstwhile documentary on Joaquin Phoenix’s retirement from acting to pursue a career as a rapper — the first question is always the same: is it for real, or is it a massive Andy Kaufman-esque put-on?

Some time ago, I placed a personal moratorium on the use of the word “brutal” in my reviews. It’s a lazy adjective, so often overused, and used to such a generally hyperbolic effect that its real power has been diffused. But I’m bringing it out of the attic today. The Killer Inside Me, Michael Winterbottom’s adaptation of Jim Thompson’s classic crime novel, is a brutal piece of cinema, and it earns that descriptor more…