What’s most striking about Woody Allen’s new comedy, a period piece about a couple of 1940s insurance investigators who fall in love while being manipulated by a greedy hypnotist to rob their own clients, is how much the writer-director has, at retirement age, begun to resemble the late William Hickey. Allen still has the same fluttery mannerisms he used to–he’s perpetually flinching–and he talks in the old alternately shy and pompous way, but he now looks wizened and creased, and his thinning hair has gone a sort of cream-colored grey. That’s why it’s more than a little creepy for him to write himself a part as the romantic foil for somebody as young as Helen Hunt. Is it really supposed to be cute, let alone credible, to watch her go bonkers over a withered, emaciated guy like him? Might it not have been better to cast somebody younger in the role? Doing so would also have given Allen the opportunity to spend more time staging “The Curse of the Jade Scorpion” a bit more skillfully. To be sure, he’s never been the most adept director in terms of composition and camera movement (Kevin Smith is in many respects a contemporary equivalent), and he’s probably quite proud of production designer Santo Loquasto and costumer Suzanne McCabe, who’ve done a good job in recreating the pre-war ambiance on an obviously limited budget, but his habit here of keeping the focus rigidly still while allowing characters to walk in and out of frame, leaving viewers to look at empty rooms for what seems an eternity, seems brutally amateurish in a guy who’s made so many movies.

All this wouldn’t matter much if “Scorpion” were a brilliantly-written piece, but in Allen’s oeuvre it probably doesn’t even rank in the upper half. It’s basically a cross between “Double Indemnity” and one of the Tracy-Hepburn dueling-colleague comedies, with a pinch of “The Front Page” thrown in for good measure. Allen is CW Briggs, the cynical, instinct-grounded investigator (just think a thinner version of Edward G. Robinson’s “Indemnity” character) who feels threatened by new efficient expert Betty Ann (Hunt). Betty Ann, meanwhile, is involved with their unctuous, married boss Chris (Dan Aykroyd). At an office party CW and Betty Ann, who espouse hatred for one another and engage in constant hostile banter, are hypnotized into professing mutual love by sleazy mesmerist Voltan (David Ogden Stiers). Voltan afterward keeps them secretly under his spell and orders CW to steal from some of the firm’s wealthiest clients. Eventually he comes under suspicion and enters an uneasy alliance with Betty Ann, who’s being strung along by Chris, to prove his innocence; she gets implicated too, and to complicate matters further, the affection that Voltan had earlier instilled in them proves to be real, concealed–as so often happened in screwball comedies–by their previous antagonism.

Obviously the picture is terribly contrived, in the manner of so many B-grade thrillers of the thirties and forties; that’s supposed to be part of its charm. But ultimately its threadbare devices–like having sequences repeatedly interrupted by a convenient phone call from Voltan, whose voice immediately turns CW or Betty Ann into a mindless automaton–come to seem simply creaky rather than fun. And Allen shows himself remarkably ungenerous by hoarding all the good lines for himself. In CW’s banter with Betty Ann, the guy nails her every time, while her comebacks are awfully flat and lame. Aykroyd’s caddish boss is played completely straight, without a hint of humor about him; he’s just an overweight bore. (Isn’t it odd how Sid Caesar became less and less funny as he got thinner, but exactly the opposite is true of Aykroyd? As he’s gotten chubbier, he’s lost the manic quality that once made him a riot.) And in smaller roles Stiers, Charlize Theron (as a Lana Turner-style femme fatale) and Wallace Shawn (as an office colleague) are simply wasted. When you get right down to it, the writer-director has fashioned the picture as pretty much a one-man show for himself, with Hunt (in a role that’s little more than a brittle variant of the part she played in “What Women Want”) as a convenient stooge. When added to the fact that Allen is more than a tad too old for his role, the result comes across as positively narcissistic.

That’s not to say that “The Curse of the Jade Scorpion” doesn’t have some amusing moments. Allen is still a talented jokester, and once in a while he comes up with a barb or a riposte that earns a chuckle. But by the standards of his best work it’s a frail, anemic trifle, a five-minute sketch inexcusably drawn out to well over an hour and a half. And maybe it’s time Woody started acting his age. His former co-stars certainly have.