Rhona Mitra (right) does battle in "Doomsday."

If you're looking for candidates for most off-the-wall movie of the 2008, you might call "Doomsday" the early favorite.

It's a post-apocalyptic thriller, where we see a future society divided by plague, including flashes of modern urbanism, a "Mad Max"-style neo-punk rock society, and a medieval-type castle-and-moat segment with guys riding horses and wearing suits of armor.

The story is this: a deadly virus spreads through the UK, devastating the northern population. The governement builds a 30-foot wall around the northern half of the country, locking everyone in and effectively quarantining the virus. For added security, machine guns are mounted on top of the wall, keeping everything vitamin, animal or mineral inside.

30 years later, the virus pops back up in "civilized" society. The government has been monitoring its sick population, and has discovered that there are survivors, prompting the prime minister (Alexander Siddig of "Syriana") to send a team of military specialists inside the walls to find out how they survived.

Leading the charge is Eden Sinclair (Rhona Mitra), a Lara Croft-style badass who has her own connection within the walls.

Writer/director Neil Marshall follows up the vicious, scary "The Descent" with a similarly unrelenting, gory, and merciless tale. When you buy a ticket to this one, be ready for decapitations, amputations and explosions aplenty.

It's an wild ride, to be sure, with a solid premise, decent enough acting and good effects. It's a rarity for a post-apocalyptic thriller to actually be this good. Filmmakers usually find themselves in a bit of a quandary with them, trying to find mainstream appeal in a decidedly off-the-wall idea, and Marshall has none of those misgivings. He crafts a no-holds-barred popcorn flick with just enough social commentary so as not to interrupt the carnage.

The film falters a bit in using cutesy dialog. Eden gets a little too deadpan in dire situations, and her blind self-assuredness pulls us out of the situation on occasion.

But that tongue-in-cheek attitude at times lets us know Marshall isn't taking things too seriously, though he sacrifices a measure of tension for it as well.

"Doomsday" isn't for everyone, but those who can stomach the blood and guts, the ride is an enjoyable one.