Quentin Tarantino: “One of the things that’s really nice about [our friendship] is we’re great audience members for each other’s movies.”

Robert Rodriguez: “I almost just make movies now so I can see them at Quentin’s house.”

—from an interview in Entertainment Weekly, June 22, 2006

THEY MET AT THE TORONTO INTERNATIONAL FILM FESTIVAL in 1992, when both of their stars were in sudden and rapid ascendance. Quentin Tarantino, then 29, was earning rapturous praise for his thriller Reservoir Dogs, which had already played that year at Sundance, Cannes, and Telluride. Robert Rodriguez, then 24, had recently made an even bigger splash, selling his $7,000-budgeted debut feature El Mariachi to Columbia Pictures and signing a two-year deal with the studio. As the story goes, they spent ninety minutes talking in a hotel lobby. Back in Los Angeles, the upstart directors discovered that they both had offices on the Sony lot.

A classic Hollywood friendship was born. The two men bounced ideas off each other for future projects. They regularly visited each other’s houses (Tarantino remained based in L.A., while Rodriguez moved to Austin). They both turned out successful sophomore efforts—Tarantino’s Pulp Fiction (1994) and Rodriguez’s Desperado (1995)—and next they turned to collaboration: the omnibus film Four Rooms (1995), to which they both contributed shorts, and the comic vampire picture From Dusk Till Dawn (1996), which Tarantino wrote and starred in and Rodriguez directed. A decade later, they’re still collaborating: Their latest team effort is the Austin-shot “double feature” Grindhouse (opening April 6), which consists of Tarantino’s Death Proof (a pastiche of late seventies/early eighties slasher pictures) and Rodriguez’s Planet Terror (a pastiche of late seventies/early eighties zombie pictures).

All of which makes this an especially appropriate time to speak an unavoidable truth: namely, that the friendship between these men might just be the most mutually self-destructive one in contemporary Hollywood. Instead of prodding each other in daring new directions, Tarantino and Rodriguez appear to have settled into the ghetto of horror and comic-book genre filmmaking; witness their work, solo and together, in The Faculty, the Kill Bill pictures, and Sin City. And rather than build upon the manic energy and formal invention that characterized their early films, they now both turn out emotionally hollow, technically flawless fanboy spectacle—it’s almost as if they’re in a competition to see who can make blood splatter more elegantly across the frame. With Grindhouse, Tarantino and Rodriguez seem a hair’s breadth away from becoming caricatures: two adult men who cling to each other—and who desperately try to relive their glorious salad days—as a means of never having to grow up.

The seeds for all this were no doubt planted long ago, probably around the time Tarantino came up with the idea for Four Rooms and invited Rodriguez (along with then-indie darlings Alexandre Rockwell and Allison Anders) to contribute. Tarantino delivered the longest, most obnoxiously self-aggrandizing short in the collection, about a high-stakes wager between an endlessly jabbering director (Tarantino) and his foulmouthed best friend (Bruce Willis). For his part, Rodriguez made a trifling farce about two kids left alone in a hotel room on New Year’s Eve (it’s a warm-up, of sorts, to the director’s Spy Kids franchise). The qualities that have come to characterize all of their recent work can be found right there: Tarantino is too busy basking in his own celebrity and too in love with his own overwritten dialogue to bother with compelling characters or an interesting story; Rodriguez is so intent upon entertaining the twelve-year-old boys in the audience that he nearly puts his adult viewers to sleep. The fact that neither director seems to have done much to curtail the other’s worst impulses in Four Rooms suggests that tough love was probably never in their emotional repertoire.

Instead, they’ve just continued enabling each other, in project after project. It’s Tarantino we have to blame for suggesting to Rodriguez that he make his third “mariachi” film, Once Upon a Time in Mexico (2003), which, as superfluous sequels go, ranks somewhere between Jason X and Karate Kid III. And while Rodriguez made no formal contribution to Kill Bill Vol. 1 (2003) and Vol. 2 (2004), it’s hard not to see his influence, especially in the first film, with its paper-thin conflicts and hyperstylized action sequences. (He’s given special thanks in the credits.) Yet there’s no humanity in Kill Bill, and no compelling reason to pay attention, either: Tarantino conceives Uma Thurman’s vengeance-seeking bride too narrowly, and he’s too caught up watching her fight (or—in Vol. 2—having her recite florid, quintessentially “Tarantino-esque” monologues) to ever let her character breathe. The director allows the juvenile impulses that had merely punctuated Pulp Fiction and Jackie Brown (1997) to completely dominate his work. A year later, Rodriguez fell into the same trap in his and Frank Miller’s adaptation of Miller’s graphic novel Sin City (2005), which also features a sequence “guest directed” by Tarantino. This unrelentingly gruesome triptych of crime stories—shot in monochromatic black and white with bursts of neon periodically lighting up the frame—is so strikingly strange and beautiful that it takes at least 20 minutes to realize that it’s also a total bore, a 124-minute movie without a single character worth caring about.

As of mid-March, Tarantino and Rodriguez were reportedly still in the editing room putting the finishing touches on Grindhouse—so the jury remains out on this latest effort. But it’s hard to approach it with anything but a heavy heart, especially if (like me) you believe that El Mariachi’s burst of cheeky energy has rarely been matched in American movies since and that Pulp Fiction remains perhaps the most audaciously conceived crime film ever made. In a promotional video for Grindhouse that you can find on YouTube, the two directors sit in the movie theater in Tarantino’s house. They talk about their enthusiasm for trashy, low-budget horror films from the seventies; Rodriguez talks about how he fell in love with the idea of a movie about a woman with a machine gun for a leg; Tarantino talks about how he wanted to “fuse” the “slasher film with high-octane car chase action.” And at some point listening to all this, you can’t help but step back and ask, How old are you guys? (For the record, Rodriguez is 38 and Tarantino is 44.)

Granted, there’s nothing ostensibly wrong with spending a career making movies for twelve-year-old boys (just ask John Woo or Brian De Palma), and certainly no one is begging either of these guys for a remake of Schindler’s List. But this compulsive need to seem “hip” and “cool” and “young” is proving hazardous to their work, not to mention their legacies. After all, you can only go on building the same old castles in the sandbox for so long before the adults stop paying attention to you altogether.

Christopher Kelly is the film critic for the Fort Worth Star-Telegram.