Here's some of the choice mysteries presented in the first reel of Headshot, a seamy, rain-drenched Thai thriller whose title concerns targeted/exploding craniums rather than 8-by-10 glossies: Why is the good-looking ex-cop (Nopachai Jayanama) shaving his head and dressing as a monk? What's with the sharply shot, genuinely upsetting assassination at a monastery? Why does a world-class knockout--Chanokporn Sayoungkul, whose dress at first seems laminated to her flesh but somehow comes off within 30 seconds of her on-screen arrival-- high-heel clop down a movie-damp city street to drop a room key at the feet of the hero and announce "I like cops"? And what in the holy hell does it mean when, after the monastery shoot-out, that cop awakens in a hospital to be told that he now suffers from "upside-down vision," an ailment winningly re-created by Pen-ek Ratanaruang, who favors tense POV shots à la first-person shooters as well as flashbacks nested within flashbacks and narration about "evil genes" and the need to seize control of humanity from the forces of evolution. The answers are neither fresh nor especially satisfying, but Ratanaruang distinguishes the hunt with his fluid kineticism, especially in the just-a-touch-too-infrequent shoot-outs and beatdowns. Those bits are cut as sharply as Jayanama's abs. The rest, not so much. The awesome shit's awesome; the ponderous is ponderous; and the bloody corpses are arranged as artfully as wedding bouquets.