Brief synopsis: A likable Everyman ends up with the girlfriend from hell, who just happens to be NYC's premiere superhero.
You really don't want to have an angry, unstable ex-girlfriend with Superman's powerset.
Of course, this could have been a movie about a guy who feels emasculated about the imbalance of power and authority in his relationship. It could have been a movie about the stress a person who constantly risks their life for others can take out on the other people in their lives. It could have been a lot of things, but it wasn't. It was just sort of cute and scary and romantic.
I don't even care that the plot didn't make sense. I don't care that the filmmakers didn't seem to understand what a secret identity is for. I do care that Thurman's neurotic girlfriend was too over-the-top, which just didn't work in a film with fantasy elements. If you have a naturalistic, realistic setting you can get pretty outre with characterization. If you have outlandish plot elements, I need to see characters that are a little higher on the bell curve to believe in them.
I get the impression they didn't care about any of that. But if you're going to make some mindless fun, I'm going to need an extra helping of the fun to make it all go down. There were too many rote moments (does every guy in a romantic comedy have to have a tactless, chauvanist, thinks-with-his-cock buddy? Why would these guys even be friends in the first place?). There were too many moments that needed a joke or a laugh that had, instead, nothing.
They shouldn't have gone in front of the cameras until they were ready to put in those payoffs.
Disappointing, but that's what I expected.