“28 Weeks Later” is the little-related sequel to Danny Boyle’s “28 Days Later,” the arty little gem that led – with a running start – the then-pulseless zombie genre into the ubiquitous presence that it is today. Released a full five years after its predecessor, and after enough zombie flicks, good and bad, to fill a shopping mall, “28 Weeks” didn’t raise hopes with its entirely different and little known actors, writers and director.

Imagine my surprise then, when “28 Weeks” rocked and shocked its way onto the exclusive list of my all-time favorite horror movies. The zombies are the still-living victims of the “rage virus,” a highly-infectious disease which, in short order, turns primates into unthinking, blood vomiting, adrenaline-pumping killing machines. After turning or killing nearly the entire populace of the United Kingdom, the infected quickly die of starvation in the final frames of “28 Days Later.” “28 Weeks Later” begins with a U.N. force establishing a heavily-fortified colony on the Isle of Dogs in London to house refugees and begin the repopulation of Britain. Reunited at the site are Don (the always fantastic Robert Carlyle) a father tormented by the actions he took to survive, and his two children, Andy (Mackintosh Muggleton), one of the most tolerable child actors ever) and his older sister Tammy (Imogen Poots). Britain is suspected completely free of the infected, but we know better, and after a slow but suspenseful 45 opening minutes, London is again turned to a living hell.

The film’s greatest accomplishment is not that it simply follows the style of its predecessor, but that it understands its message: that sheer spectacle doesn’t create fear, that realism and pathos create gut crawlies in ways that even the flashiest of effects can’t craft alone. “28 Days Later” was a masterpiece because it wasn’t about shock but survival, families, desperation and moral relativism. Even the genesis of the virus wasn’t about weird science, but the evil that men do to each other, and the film’s most disturbing scenes involved violence wrought by the survivors upon each other.

Although those who like their buildings blown-up and bullets flying may actually prefer this movie to “28 Days” due to its relentless action, there are still a few problems in the movie that keep it from attaining the status of its predecessor. Although the movie avoids action movie logic to an impressive degree, one particularly flagrant, if necessary, plot hole emerges in the treatment of the citizens during the initial outbreak (it seems that the army’s contingency plan is expressly designed to create a frantic action sequence). But the verve with which the sequence is executed quickly buries that feeling of discontent. London is used terrifically in the film, even if the filmmakers seem a little too fond of it: the film’s protagonists counter-intuitively circumnavigate London four times in the course of the movie, running by as many landmarks as possible, as if their escape route were plotted from a Frommer’s guide.

The film’s more garish Hollywood leanings, including a few spectacular helicopter bits, are so original and executed with such panache that their excess is quickly forgiven. “28 Weeks Later” understands, like so few films do, that watching an aerial bombing is infinitely more effective from ground level, that a silent cloud of nerve gas is more terrifying than said explosion, and that being chased by an insane parent is far more terrifying than a limping corpse, a terror all too rare in film today.