This is the second "old guys doing young guy stuff" that Robert DeNiro has starred in this year, and it is by far the weirder of the two. That may be because it feels like a studio movie caught somewhere between two very different schools of comedy. The script is credited to Tim Kelleher and Rodney Rothman, which could account for the split-personality of the film. Kelleher is the writer of "First Kid," credited as a staff writer on "The Arsenio Hall Show" and "The Pat Sajak Show," while Rothman is a frequent collaborator of Nick Stoller's, one of the major creative voices on "Get Him To The Greek" and "The Five-Year Engagement," the author of the sharp and funny "Early Bird: A Memoir Of Premature Retirement," and the writer/producer of the crazy science-fiction comedy "The Something," which is in development at Universal. And just in case the script wasn't already struggling to fit these two very different voices, the film is directed by Peter Segal, responsible for such uneven efforts as "Anger Management," "Naked Gun 33 1/3," "Nutty Professor II," and "Get Smart."

As a result of all of these voices in the mix, "Grudge Match" never quite lands on a voice. Is it a silly comedy about two old men trying to get back in shape so they can beat the hell out of each other? Is it a character piece about what it is that keeps the various fires in our lives burning? Is it a direct parody of both "Rocky" and "Raging Bull" at the expense of the aging icons who starred in those films in the first place? "Grudge Match" is all of those things and none of them, a Frankenstein monster of a movie that isn't bad so much as it is confused.

Sylvester Stallone plays Henry "Razor" Sharp, and Robert DeNiro plays Billy "The Kid" McDonnen, both of whom held the heavy middleweight championship at different points. They both have undefeated records with a single exception, each of them having lost one fight to the other. A scheduled third fight never happened back in the day because Razor walked away from fighting, leaving the public mystified and The Kid unsatisfied for decades. Now, 30 years later, the son of the promoter who made money off the two of them, Dante Slate Jr (Kevin Hart) approaches them about an opportunity that's come up. Someone wants to motion-capture each of them for a boxing video game that will allow console gamers to finally play out the final bout themselves. Razor wants nothing to do with it at first, but he's trying to take care of the nursing home bills of his former trainer, Lightning Conlon (Alan Arkin), and he finds himself agreeing despite his strong reservations.

The film is definitely on Razor's side from the very start. The reason he walked away from fighting is because of a personal wrong that was done to him, and he has every reason to hate The Kid. DeNiro seems to take pleasure playing a loudmouth riff on Jake LaMotta. There's a scene early on where we see him onstage at the restaurant he owns, doing a drunken stand-up act with a puppet, and it's hard not to make the connection to the scenes from "Raging Bull." Likewise, there are scenes where they make direct nods to "Rocky," like having Stallone drink a glass of raw eggs for breakfast or going to a butcher's freezer while training. They even use footage from those movies, manipulated by computer, to create the footage of the first two fights between the guys. As a result, it's hard not to be constantly aware of this as a reaction to other movies more than a movie that exists on its own.

Stallone underplays things nicely for the most part, and at least DeNiro seems like he's engaged. He's got the most sides of a character to play as The Kid tries to make up for past transgressions, reuniting with a son he never knew he had named BJ (Jon Bernthal) and his grandson Trey (Camden Gray), and the movie's most grounded and real moments deal with the ways The Kid constantly lets down the people around him. I never really caught the resemblance that Bernthal has to a young DeNiro, but it works as a casting idea, and Bernthal tries his best ot make it count. Kim Basinger, positively flabbergasting for a woman in her 60s, seems to be relaxed and having fun, but despite being a key character in terms of the film's plot, she still feels underwritten. The best chemistry in the film is between Alan Arkin and Kevin Hart, constantly trading abuse, and even if some of the jokes are too easy (Arkin referring to Hart as "Webster" is the very definition of a cheap laugh), the two of them have some real energy between them that keeps it interesting.

There's not a single narrative surprise here, and because the film isn't willing to let The Kid be a real villain, the ending finds a way to make both of them look good. I wish the movie didn't pull so many punches, though. If they'd just pushed it to be a little more honest, a little more grounded, a little more character-driven, it could have been a lovely subversion of what we know about these guys as onscreen characters. Instead, it feels to me like a half-hearted attempt, a film that didn't fully commit, and the result is pretty much just a muted near-miss.

"Grudge Match" opens everywhere on Christmas Day.