This may be another Marvel comic superhero movie rated PG-13, but it is a much darker story than “Spiderman,” and parents whose 8 and 9 or even 13-year-olds loved that movie should think carefully before agreeing to let them see this one.

Matt Murdock lives in “Hell’s Kitchen” a tough part of town where bullies of all kinds prey on the vulnerable. His father, a boxer, is killed for refusing to take a dive in a fixed fight. Matt, blind from an accident that also left him with his other senses super-enhanced, vows to become a righter of wrongs and a force for justice.

But is he a force for justice or a murderous vigilante? When he loses a case in court, allowing a rapist to go free, Daredevil doesn’t just go after him; he slaughters a whole roomfull of bad guys. At least, they must be bad guys, even though we don’t really see them do anything bad except for looking tough and fighting for their lives. Even Daredevil himself is not entirely sure that he is one of the good guys.

Murdock meets Elektra, whose fragrance is so tantalizing that he follows her out of a coffee shop. They end up taking each other on in a fight in a playground that serves the same function for them that dance numbers did for Fred Astaire and Ginger Rogers — it’s their way to size each other up, and it’s their foreplay. At one point, he says, “Are you holding back?” she says, “Yes,” and he says, “Don’t.” Clearly, they were made for each other.

But there are complications, mostly the work of a crime kingpin named…Kingpin and his hired Irish assassin, Bullseye (Colin Farrell, for once using his original accent). There are misunderstandings, choices, and lessons, but mostly there are fights.

The fights are very good, but it is clear that that is where most of the creative energy went in this movie. Affleck does not act very much, and if he did, most of it would be hidden by Murdock’s sunglasses and Daredevil’s mask. Garner brings energy and freshness to her role, and Farrell is, as usual, the most watchable part of the movie. There are some fun in-jokes, including appearances from Marvel’s Stan Lee and onetime Daredevil writer Kevin (Chasing Amy and Dogma) Smith. But the script is flat, mostly just space between fights. Sometimes loud noises incapacitate Daredevil, sometimes they don’t. He is badly injured, and then he isn’t. These are continuity errors that are evidence either of laziness or, more likely, some recutting after early screenings.

Parents should know that this movie is more somber and much more violent than Spiderman, including many deaths. There are sexual references and non-explicit sexual situations, including a reference to rape and a sexual encounter between people who do not know each other very well. There is some strong language and some drinking and smoking.

Families who see this movie should talk about why we don’t take the law into our own hands. How do you become a killer without being one of the bad guys? Why, when most superheroes have fantasy special powers, is a character who is disabled so appealing?

Families who enjoy this movie will also enjoy X-Men and Blade.