When a film you might not have much hope for turns out better than you expected, it’s always a pleasant surprise—even when it’s a picture like this remake of George Romero’s 1973 shlockfest about a small town reduced to murderous madness by toxins in the water supply and the military’s attempt to wipe out the deranged population, which is obviously not designed to be a “pleasant” viewing experience. This new version of “The Crazies,” cannily directed by Breck Eisner, may not break new ground, but like Zack Snyder’s 2004 reworking of Romero’s “Dawn of the Dead,” it treads familiar territory with considerable dexterity.

The original picture was, of course, an extremely low-budget, seat-of-the-pants follow-up to Romero’s breakthrough “Night of the Living Dead,” and frankly it doesn’t hold up all that well. Eisner’s is certainly slicker and better appointed, marked by a solid production design by Art Menzies, spiffy art direction from Greg Berry, and crisply atmospheric cinematography by Maxime Alexandre—as well as a flavorful score by Mark Isham.

What makes “The Crazies” work, however, are Eisner’s skilled handling and the efforts of a cast that’s stronger than one usually finds in such fare. Timothy Olyphant and Joe Anderson star as Sheriff David Dutton of Ogden Marsh, Iowa, and Deputy Russell Clark, who discover a plane wreck in a nearby lake—the source of the deadly pollution—after Dutton has been forced to shoot a local who threatened a couple of high school baseball teams with a rifle. After other people in the community go off on murderous rampages of their own, the military quarantines the whole town, including Dutton and his pregnant wife Judy (Radha Mitchell).

The central question is whether the authorities are interested in diagnosing the cause of the outbreak and treating the locals, or simply in exterminating them and sweeping the whole business under the Midwestern grass. So anti-government paranoia lies at the root of the plot. But most of the action is devoted to the usual sort of chases, hair’s-breadth escapes, and—most notably—bloodletting and evisceration. The film necessarily plays into the new era’s taste for gore and guts, as well as explicit makeup in the case of people in the later stages of the infection. But in general Eisner doesn’t go as far in that direction as many of his predecessors have done, and the picture isn’t as repulsive as most, preferring cleverness over mere grossness. It does, however, begin to run out of gas in the final stretch.

Olyphant, a good actor, also gives it a touch of class, doing a solid job even if neither the sheriff nor his wife (also well played by Mitchell) is terribly well developed as a character. Anderson has a showier role as the lawman who’s none too self-controlled even before the plague strikes, and everyone else does at least a professional job.

“The Crazies” isn’t the best title in the world, but you can blame Romero for that. And this movie isn’t the finest horror picture in the world, either. But it’s sufficiently well done to allow one to say that you’re not nuts to go see it.

And how can you not like a movie about a government even more berserk than its infected citizens and the madness of the military mind that manages not one but two musical references to “Dr. Strangelove” in the first half hour?