Cillian Murphy in '28 Days Later'

Fans of movies such as George Romero's classic Night of the Living Dead trilogy and Boris Sagal's 1971 apocalyptic The Omega Man will find buckets of flesh-eating fun in Boyle's hyperactive update of the infernal and always-entertaining battle between the living and the undead.

28 Days Later dawns with a pack of animal-rights renegades – who apparently value human life much less than that of cuddly, delicious critters – breaking into a primate research facility. Ignoring all warnings about dangerous infection, the self-appointed SWAT team frees a lab full of caged chimpanzees that had been happily watching banks of video monitors running images of graphic violence. Cruel, but it beats an Oxygen Network marathon any day. Clearly not happy to have their cable TV cut off, the permanently enraged primates immediately go bananas, slay their rescuers and escape to infect the general population with highly contagious monkey madness.

28 days later (hey, great idea for a title), Jim (Cillian Murphy), a bike messenger, wakes from a coma in the pillaged wreckage of a London hospital. Upon leaving, he finds, with the help of some very ingenious camera work, the city deserted with no one to answer his calls for help. Until nightfall, when in a ruined chapel, Jim is attacked like a hot-buttered altar boy by a psychotic, blood-eyed priest and is chased by a mob of similarly bloodthirsty crazies back into what promises to be one heck of a long dark night.

Still clueless as to what changed Jim's jolly old England into one huge Ozzfest, he is rescued briefly by Selina (Naomie Harris) and Mark (Noah Huntley), a pair of "survivors." They explain the origins of the murderous "infection" to Jim, as well as how it can be transferred in a drop of blood, and that the only cure is to be burned alive or chopped up in little pieces. Man, and you thought cooties were bad.

Moving fright along, the trio of survivors takes a relaxing day trip up to Depford to find Jim's mom and dad dead from a pill-induced suicide pact, "Don't wake up," being their last words of parental advice, presciently penned while Jim was still in his coma. Soon, after another zombie attack, Mark is infected and cold-bloodedly "cured" by Selina. Jim and Selina then travel back in the gallows of swinging London, where they meet another pair of survivors: the father-daughter team of cab driver Frank (Brendan Gleeson) and fifteen-year-old Hannah (Megan Burns).

Together the four set off for Manchester in Frank's taxi, following an automated military radio signal promising safety and an "answer" to the infection. Jim, Selina and company battle their way past hordes of undead so hideous the Lord of the Rings would drop his bling-bling and make a post-haste about face.

Eventually, three remaining survivors reach the militia compound only to find that despite initial pleasantries, the officers are far from gentlemen and the fight for their lives is equally far from finished.

In case you hadn't noticed, or rob graves on your days off, there aren't a lot of laughs here, save for Frank keeping the meter running in his cab and leaving his credit card at a ransacked supermarket. But the relief that these bits and a few others provide are welcome shots of humanity that save 28 Days Later from falling into its own meat grinder. And if you still want to know what's the point of all this chaos and bloodshed; aside from being the coolest-as-shit zombie flick of the past twenty-five years, there's also a cunning comment or two about violence in media, social rage and mankind's need for a worldwide timeout.

Not for the feint of heart, high of blood pressure or loose of stools, 28 Days Later ranks severed-head-and-shoulders above half-baked horror shows like 2001's Alejandro Amenabar's lackluster The Others. And even if Boyle's brew isn't as creepy as, say, Gore Verbinski's 2002 remake of The Ring, clever filming and crafty performances, not to mention Alex Garland's (novelist of The Beach) scalpel-sharp script keep 28 Days Later's plot boiling over with gruesome grit and genuine glee.

It might not keep you up tossing and turning until Halloween, but the shell-shocked feeling experienced upon exiting 28 Days Later makes everyday disasters like SARS, the Middle East, and Martha Stewart seem somehow not so terrifying. And to quote madhouse-ready Martha herself, that is "a good thing," indeed.