Since the project was first announced, Quentin Tarantino and Robert Rodriguez's geek extravaganza Grindhouse has billed itself as being more than just a motion picture. Indeed, this 191-minute butt-number aspires to be nothing less than an honest-to-God time machine built to transport viewers back to the '70s when titles like Brotherhood of Death and The Blood Spattered Bride were proudly displayed on the marquees of skeevy Times Square cinemas. Not only does Grindhouse offer two feature-length exploitation films for the price of one, but it also includes trailers for four other schlock-fests, retro in-theatre announcements. and a super-low-budget ad for a fast-food joint in Austin, Texas, where both pictures were shot. The only thing missing is one of those "Let's all go to the lobby" jingles, but then you wouldn't have wanted to linger in the lobby of an actual grindhouse for very long anyway.

It would be antithetical to the grindhouse spirit for Grindhouse to be a grade-A classic, and the harsh reality is that it's not. Rather, it's an ungainly creature that alternates moments of sheer brilliance with moments of stunning banality. Fortunately, the former end up outnumbering the latter. The evening gets off to a strong start with a Rodriguez-directed teaser for a revenge flick called Machete, about a hired gun who wreaks bloody havoc on the men who left him for dead. This leads into the first feature, Planet Terror, Rodriguez's riff on zombie favorites like George Romero's Dawn of the Dead and Lucio Fulci's Zombi 2, in which a top-secret military experiment transforms the residents of a small Texas town into the walking dead. When the last pint of zombie blood has been spilled, moviegoers are treated to another round of fake trailers--including Rob Zombie's self-explanatory Werewolf Women of the S.S., Edgar Wright's uproarious Hammer Films homage Don't and Eli Roth's holiday-themed slasher spoof Thanksgiving--before the opening credits roll on Death Proof, Tarantino's high-octane battle of the sexes that pits psychotic stunt driver Stuntman Mike (Kurt Russell) and his killer car against two very different groups of young women. When the lights finally come up, you'll stumble out of the theatre riding a wave of emotion that's one part joy at what you've just witnessed and one part relief that it's finally over.

In interviews, Tarantino and Rodriguez have stressed how seriously they approached the task of recreating the look and feel of '70s exploitation cinema. It's certainly difficult to fault the finished product on a technical level. With the aid of some post-production magic, both films have been aged to resemble the scratchy, worn-out prints that toured the country on the grindhouse circuit. The directors also make sure to toss in such industry staples as blatant continuity errors, ragged cuts and even missing reels. Although these movies may have the appearance of generic exploitation pictures, at heart they are the purest possible expressions of each filmmaker's personality and general aesthetics. Thus, Planet Terror is a live-action cartoon while Death Proof is a loose and rambling talk-a-thon punctuated by moments of viscerally thrilling ultra-violence.

It's safe to say that Rodriguez's entry will prove more popular with general audiences than Tarantino's. Even though Planet Terror lacks the sharp wit and--don't laugh--intellectual rigor of such superior zombie pastiches as Shaun of the Dead and Dead Alive, it's still a lively crowd-pleaser that sports some genuinely inventive (and eye-poppingly gory) set-pieces. The best of these are a daring rescue mission at a zombie-infested hospital and the climactic battle in which the surviving humans massacre their flesh-eating enemies with a helicopter's propeller blades as well as that machine-gun leg you've seen in all the ads. As usual, Rodriguez can't fashion these isolated incidents into a coherent narrative and, in fact, Planet Terror grinds to a halt every time he allows the characters to engage in conversation. Just try not to roll your eyes during the scenes between mysterious hero El Wray (Freddy Rodriguez) and his estranged stripper girlfriend Cherry Darling (Rose McGowan), the owner of the aforementioned machine-gun leg. (To be fair, their bland romance does yield one of the movie's best gags: a sex scene that's so hot, it literally burns a hole in the film.) It's clear by now that Rodriguez will never be one of his generation's all-time greats, but it must be said that the guy can dispatch zombies with flair.

If his buddy has trouble getting his characters to talk to each other, Tarantino's failing is that he can't make them shut up. Of course, the filmmaker's way with words has always been central to his mystique, but this is the first time where you might find yourself wishing he'd just get to the freakin' point already. Part of the problem is that Tarantino has split his film into two acts that are only casually linked. The first half, which follows a group of Austin gals over the course of one long day and night, comes across as the Quentin Tarantino version of a Richard Linklater movie, complete with a gruesome car crash at the end. Act II fits more squarely into the grindhouse tradition, incorporating elements from films like Vanishing Point, the original Gone in 60 Seconds and Russ Meyer's immortal Faster, Pussycat! Kill! Kill! The movie concludes with a stellar car chase that's worth the wait (with Kill Bill stuntwoman Zoë Bell playing herself), but getting there can be slow going, particularly when confronted with an extended conversation in a roadside diner that seems designed purely to test the audience's attention span, not to mention their bladder control.

Nevertheless, it would be a mistake to write Death Proof off entirely. It may not provide the immediate thrills of its predecessor, but Tarantino is up to something here that's ultimately far more interesting than all of Planet Terror's zombie bloodshed. He's produced a grindhouse movie that can be read as a critique of certain grindhouse conventions, most notably the celebration of an outdated brand of machismo. Grindhouse drives home the fundamental difference between these filmmakers: Where Rodriguez always looks to satisfy the audience's expectations, Tarantino is out to defy them.