The Mamet-rigged cons and double crosses in Redbelt may not be as complicated and elegant as the ones in, say, The Spanish Prisoner, Spartan, or, my favorite Mamet film, the criminally underrated (and unavailable-on-DVD), Homicide, but Redbelt towers over those films in terms of emotional resonance and giving the audience a hero that it can not only sympathize with but also root for. That's a big deal. I typically don't go into a Mamet movie (even on repeated viewings) cheering for the protagonists—I'm too busy keeping up with the plot twists, the stylized dialogue, the smoke and mirrors. (One exception is, perhaps, State and Main, his terrific comedy about Hollywood.)
Many of Mamet's regulars who I've come to know and love are here: Joe Mantenga, Ricky Jay, Rebecca Pidgeon, etc. But its Chiwetel Ejiofor, that mind-bogglingly great British actor from Dirty Pretty Things and Melinda and Melinda, that brings gravitas not only to his role as a stoic Jiu-Jitsu instructor with a strict code of honor (and with nagging money problems) but also to the entire film, which culminates in a rousing fight scene.
Moviegoers may find some of the plot points a bit contrived, but I get the feeling that Mamet has never minded the artifice. In his films, he generally seems to be more concerned with the mechanics of conning the audience, rather placating them with the illusion of reality. But in Redbelt, he also seems to want you to feel something. Diverting your intellect by aiming for your heart.