War movie, horror movie -- the difference is negligible in the grim sequel to last year's hit remake of Wes Craven's 1977 mutant thriller. After a grisly childbirth and some gory killings, the real action starts with a group of gung-ho National Guardsmen blasting their way through Kandahar. It proves to be a training exercise in the southwestern desert, thank God, but the troops are being watched by a real menace: the man-eating spawn of 1950s nuclear testing, who have learned a few things about strategery as they lure the soldiers into a killing ground of rocky hiding places and booby-trapped tunnels. Yes, the most assured fighting men are the first to go; yes, the company peacenik (Michael McMillian) will undergo a Straw Dogs conversion to lethal force. Directed by Martin Weisz from a script by Craven and his son Jonathan, the movie has already bummed out the fanboys with its paucity of cool kills -- this despite a genuinely unnerving who's-out-there use of shallow focus and a mortality rate in the high double digits. But for anyone other than hardcore gorehounds, this flipbook of deliberately invoked global-unrest horrors, from friendly-fire killings to rape as a breeding weapon, is effectively mean and unrelenting -- and pretty far from fun.