A cannibalistic charbroil is at the center of Doomsday, writer-director Neil Marshall’s playfully perverse movie mash-up of the macabre. For those wondering, an extra-crispy British mercenary resembles roast beef. Fitting, given how Marshall gorges himself at an all-he-can-eat buffet line of film homage for a crazy-fun apocalyptic thriller.

Likely to be 2008’s most entertaining film withheld from critics (it opened last week), Doomsday loudly and proudly works fewer nerves than Marshall’s acclaimed The Descent. In that measured tale of mounting dread, Marshall forged the monster-movie template into forceful feminism as Ridley Scott did with Alien. Yet even though Marshall’s menu will never evolve to Scott’s variety, it’s fine to pig out on greasy, juicy bangers and mash such as this.

Marshall piles on helpings of George Romero’s rage, George Miller’s mayhem, James Cameron’s momentum, Paul Verhoeven’s viscera, John Carpenter’s cynicism, Scott’s sense of setting and John Boorman’s meaty medievalism. (Even Tyler Bates’ music-score garnish hijacks the ragged rumble of Pink Floyd’s The Wall and rock-orchestra crescendos of 28 Days Later …). Yet Marshall uses a fresh plate each time through, distinctly drawing each of Doomsday’s hell-raising segments.

After its 105 minutes have zipped by, Doomsday has had about five different feels, each delivering on promised giddy grindhouse thrills. It’s set in 2035, about 25 years after a deadly virus called Reaper all but wipes out Scotland, a nation quarantined by a wall blocking it from all sides.

Just as Reaper resurfaces in a frighteningly overcrowded London, satellite photos reveal living, breathing humans are alive and well over the Scotland wall. Supposing there’s a cure there somewhere, a team of scientists and soldiers — led by one-eyed, hard-edged commando Eden Sinclair (Rhona Mitra) — scales the wall only to find remnants of several sick, twisted societies.

Marshall’s alchemy of anarchy in the U.K. kicks up a notch with Sol (Craig Conway), a flesh-eater with a theatrical flair who turns his meals into punk-opera street spectacles. Aided by lackeys wearing nose-to-ear chains that would make Jane Child smile, Sol ambushes Eden and her team. But a successful escape is short-lived given that Scotland’s highlands are now anything but quaint.

Mitra never oversells Sinclair’s steeliness, and the supporting cast boasts good-time slumming from elder statesmen Bob Hoskins (as Sinclair’s Cockney-accented boss, barking phrases like “Don’t git ya knickas in a twist”) and Malcolm McDowell (as the Col. Kurtz-like Dr. Kane).

Yet it’s sheer propulsive movement that is Doomsday’s real draw. Its copious action sequences and attention to desolate detail make it look twice as expensive as its $26-million budget. A climactic car chase hits huffy highs with clouds of diesel smoke and body parts clanging off the camera. And Marshall is unafraid of gallows humor (guess how a Fine Young Cannibals song is used) or sight-gag wit (a “gift shop” sign on a tourist castle now used as the real thing).