Director Danny DeVito, who specializes in biting dark comedies (1987's "Throw Momma From the Train," 1989's "The War of the Roses," 2002's "Death to Smoochy"), does it again with "Duplex." An occasionally uproarious entertainment, it is superior to all of the above because it keeps its edge intact without wavering too far into the meanspiritedness that has plagued some of his earlier work.

Novelist Alex (Ben Stiller) and magazine editor Nancy (Drew Barrymore) are a loving yuppie couple who, in planning a future that involves children and a safer environment, decide to move from their cramped Manhattan apartment into a Brooklyn townhouse. The spacious duplex they are offered is ideal for raising a family, and Realtor Kenneth (Harvey Fierstein) assures them that their upstairs tenant, the elderly Mrs. Connolly (Eileen Essel), is nearing the end of her life. Once she passes away, they can have the whole place to themselves. Upon moving in, however, Alex and Nancy discover Mrs. Connolly to be the tenant from hell, a sickeningly sweet and healthy bat who keeps them up all night with her television and is constantly demanding chores of them. Driven to the point where they can't take Mrs. Connolly anymore, Alex and Nancy decide that a lethal plan of action may be their only answer to living happily ever after.

Written by John Hamburg (2000's "Meet the Parents") and Larry Doyle (TV's "The Simpsons"), "Duplex" is fast-paced, witty, and expertly set up to maximize its comedic potential. One of the more consistently funny motion pictures of the year, the film uses all avenues of humor—physical, verbal, and scatological—to garner a heaping of major laughs. Comic highlights include Alex's trip to the pharmacy and grocery store with Mrs. Connolly, who counts everything from her prescription pills to grapes and blueberries; a feud concerning Mrs. Connolly's clap-sensitive television; Alex and Nancy's voyage to picking up the flu so they can pass it on to Mrs. Connolly; and Mrs. Connolly's description of the stairs' carpeting: "It's looser than a Dublin whore!"

Because the viewer is supposed to like Alex and Nancy, its most tricky hurdle was clearly to keep them sympathetic even as they plot the murder of a feisty old lady. Director Danny DeVito succeeds splendidly at this. Mrs. Connolly is maddeningly hateful by the very nature of her habits and selfishness, and her kindly outward demeanor only makes her all the more spiteful. When Alex and Nancy take matters into their own hands, their choice is truly understandable.

Ben Stiller (2001's "Zoolander") and Drew Barrymore (2002's "Charlie's Angels: Full Throttle") prove to be a dynamite team who play the realism out of every situation while getting to put their comedic skills to grand use. Alex and Nancy's frustrations over Mrs. Connolly are easily identifiable, as everyone has had someone in their life who has rubbed them the wrong way, and Stiller and Barrymore do fine work in keeping their character's likable but at the end of their ropes. As good as they are, the true star of the film is 86-year-old newcomer Eileen Essel as Mrs. Connolly. Essel is a comic genius in her every moment on screen, full of energy, syrupy sweetness, and feuding grotesquery.

The first half of "Duplex," in which Alex and Nancy are driven mad by their tenant, is better than its latter, where they go to any lengths necessary to kill her. While the movie is wickedly funny and full of energy throughout, the very lengths that Alex and Nancy do go through straddle the lines of implausibility (even for a comedy). Their willingness to destroy their house in order to off Mrs. Connolly seems nonsensical, since that is exactly what they are fighting for. Despite its shortcomings as it races to the finish line, they cannot lessen the dark delights and sizable guffaws that "Duplex" otherwise offers throughout its 88-minute running time. The film is undemanding, sharply conceived (its twist ending works even better than it should), and a whole lot of fun.