"My Super Ex-Girlfriend" is a romantic comedy in which one-half of the couple is a powerful superhero. It's a fresh idea, and the possibilities for comedic fodder are plentiful. It comes as a missing opportunity, then, that the film is sparkless in the romance department and the laughs are few and far between. Take away the superhero angle and the solid special effects and what one is left with is a potentially wry love story done in by bland writing and a mean-spirited revenge plot that takes over midway through.

Matt Saunders (Luke Wilson) is a Manhattan architect with eyes for his sweet and already-taken co-worker Hannah (Anna Faris). His romantic sights suddenly shift when he spots mousy but cute art gallery worker Jenny Johnson (Uma Thurman) on the subway. She rebuffs Matt's advances at first, but when her purse is stolen and he manages to retrieve it from the thief, he suddenly becomes her hero. What Matt doesn't know at first is that Jenny is an even bigger hero—a famed New York City superhero, in fact, named G-girl.

Their relationship, which starts off with promise and leads to Jenny coming clean about her secret identity, quickly grows rockier when her overbearing clinginess becomes too much to handle. Suffice it to say, the break-up does not go smoothly, and Matt finds himself facing the increasingly dangerous wrath of a superwoman scorned. His situation is only destined to get worse when Jenny discovers he and the newly single Hannah have fallen for each other.

Director Ivan Reitman (2001's "Evolution") scored big-time with 1984's "Ghostbusters" and its 1989 sequel, which were also comedic fantasies set in the Big Apple. There was a sense of wonder and innovation to those two classics, both of which still hold up amazingly well today. By comparison, "My Super Ex-Girlfriend" is a stale swab of cotton candy. There is a certain level of intelligence brought to the first half-hour as Matt and Jenny begin dating. Matt senses something strange about her—the physical force of her love-making to him leaves a hole in the wall behind the bed—and it is rather refreshing that Jenny lets him in on her superhero alter-ego almost immediately thereafter. Had the film proceeded to explore this unconventional situation, with Matt trying to come to terms with this notion and retain his masculinity while dating a woman far more powerful than he'll ever be, Reitman might have been onto something.

Instead, their parting of ways and Jenny's subsequent vow for revenge takes the air out of the picture's sails. From this point, "My Super Ex-Girlfriend" isn't fun at all as director Ivan Reitman and screenwriter Don Payne basically repeat variations of the same scene over and over as the off-balance Jenny destroys Matt's apartment, gets him fired from his job, and even unleashes a shark on Matt and Hannah when she catches them in bed together. Amidst all of the havoc are a dreary second love story between Matt and Hannah that has half the chemistry as the earlier one involving Jenny, and a slew of predictable one-liners courtesy of Rainn Wilson (2003's "House of 1000 Corpses"), as Matt's shallow, dating-challenged pal Vaughn, and Wanda Sykes (2005's "Monster-in-Law"), as Matt's by-the-book boss Carla Dunkirk. When a movie underutilizes the firecracker comic talents of someone like Sykes to the point where she doesn't get one laugh, it should be seen as a warning that the script needs another re-write.

As the in-over-his-head Matt, Luke Wilson (2005's "The Family Stone") plays the straight man to Uma Thurman's (2005's "Prime") zany, unhinged Jenny. Wilson is a naturally amiable actor, but he's done better work in the past and had roles with far more depth than this dull protagonist. Thurman, meanwhile, proves her comedic chops and then some as Jenny/G-girl, a paranoid woman who saves people's lives out of responsibility rather than because she wants to. The film's most wickedly funny scene finds Matt begging Jenny to stop a missile headed straight for New York when all she wants to do is order her dinner at a restaurant. Thurman's disgruntled facial expression as she begrudgingly takes off to save the lives of millions is priceless, and also a surefire signal that the movie would have been more successful and a whole lot funnier had Thurman not been written to play second banana to Wilson's Matt.

As Matt's true love Hannah, Anna Faris (2006's "Scary Movie 4") portrays what could be her most down-to-earth role to date; she is okay with the material provided, but her character is too idealistic to be interesting. Last but not least, Eddie Izzard (2004's "Ocean's Twelve") is a standout as Professor Bedlam, the former best friend of Jenny and current archenemy to G-girl. As Professor Bedlam sets out to reverse Jenny's powers out of spite for the way she treated him in their teenage years, it becomes clear that he isn't the dastardly villain he strives to be. Izzard plays the part with a twinkle in his eye and a self-knowing edge; Best of all, he isn't the one-dimension baddie he seems to be at first sight.

"My Super Ex-Girlfriend" ends on a clever note that equates a man being left to hold the pocketbook of his partner while she flies away to fight crime to a man put in the same position while his partner heads to the restroom. Otherwise, the movie doesn't leave room for much thought, the stock plot developments and technical credits, including a generic music score by Teddy Castellucci (2006's "Just My Luck"), turning what could have been imaginative and adorable into a run-of-the-mill revenge fantasy. A last-act confrontation between would-be soul mates, played out in front of a crowd of onlookers at a fashion show, climaxes with everyone clapping and giving approving nods. The dearth of creative inspiration in this woefully clichéd sequence is the perfect capper to a film that simply goes through the paces more often than it excels at its initial ambitions.