The real reason—perhaps the only reason—to watch Righteous Kill is the rare match-up of screen giants Robert DeNiro and Al Pacino.

While they are forever linked to one another in acting style, cinematic era and New York attitude, they actually have only appeared in the same film twice (The Godfather, Part II and Heat) and have only shared screen time in Michael Mann’s bank heist epic. Unless someone films The Godfather: The Golden Years or Bucket List: New York, any time they get together could be the last time.

So it’s pleasing to see that in this Jon Avnet crime thriller, we have two old horses out to do honor to their reputations. The actor’s craft in Righteous Kill somewhat neutralizes its spastic editing, logical leaps and crooked storytelling.

The legends play longtime police detective partners on the trail of a serial killer who leaves lousy poetry at the crime scenes. The pair comes from that Hollywood version of New York where every police detective is hardball and streetwise. Slap the cuffs, read the rights, and kick the stomach. Soon police suspect the killings are being perpetrated by a policeman. Suspicion falls on one of the partners. But is he really the guy?

While no one will mistake Righteous Kill for their best work, it’s still nice to see the two actors in good form, as they haven’t exactly been throwing down aces lately. Pacino, in particular seems more comfortable here than he has in a long time – looser, funnier, more generous, and freed of the burden of delivering “Al Pacino” that has pestered recent performances. DeNiro dusts off the intensity that so long has been associated with his work.

What the performances bring to the table, the dull-headed mystery brings down. It can’t decide whether it’s a whodunit or a how’d-they-do-it. As the answer gets more and more obvious, the film takes more and more time to get there. A film that begins with frantic editing creeps to an end with scenes that linger. And linger. And linger.

Some of the film’s silly improbabilities are really a riot. Have two senior citizens ever had more active sex lives? How do you hit a skateboarder with a clean shot right between the eyes? How could a cop kill 14 people related to his cases without getting nabbed around, say, five? Others are not as funny. Does every woman need to be a victim? Does every black man need to be a criminal?

Righteous Kill is a bit like a visit to older family members. A little bland and old-fashioned, but good to see that the folks can still get around.