This is one of those superhero spoofs like MYSTERY MEN or THE SPECIALS, so if you did not enjoy those movies you should avoid this. On the other hand, if you dug those movies then you'll definitely dig this. In fact, I think this movie is rather brilliant and I'm surprised it hasn't been done before.
The premise is that a guy (Luke Wilson) starts dating a wallflower, who is slightly crazy and very needy, and he finds out that she's really "G-Woman" (Uma Thurman) who is basically the female equivalent of Superman. At first he thinks this is cool but when he realizes that he's not in love with her but is in love with a female co-worker at his office, he dumps her, which is a big mistake. She puts holes in his New York apartment roof, hurls his car into orbit and even throws a live shark at him. If you ever had a crazy girlfriend you can definitely relate to his predicament (which definitely makes it a horror story!).
The special effects are great, some of the situations truly hilarious (such as the sex scenes) and the relationship between the super-heroine and her arch nemesis is a hoot.