There's something undeniably throwbacky about Hit & Run, which I am tempted to call a romantic comedy structured around car chases in lieu of having any better generic framework for it, though what it is a throwback to, I cannot quite say; unlike, for example, the grind house homages of the Quentin Tarantino school, it doesn't start and end as a love letter to '70s schlock cinema, though there's certainly an unmissable '70s tang to the way the film worships at the holy foot of the American Muscle Car; at the same time, "is it violent action? is it feel-good comedy?" tension of the entire project is reminiscent of dozens of '80s films, while the meandering dialogue that frequently puts a chase scene on hold to allow to characters to debate the ethics of bigotry, homosexuality in the digital age, or what causes men to like big cars comes straight from the talky American indie scene in the '90s.

Perhaps the only way to really pin the film down is to assign it to the category of "things that Dax Shepard likes", for Shepard, who I last recall thinking about sometime in the middle of the last decade, writes, co-directs (with David Palmer), and stars in this movie that, at a certain remove, functions solely so that Dax Shepard can do cool things: drive big cars fast and spin them around in circles, fire handguns, flirt and make out with real-life Shepard fiancée, the unbearably cute Kristen Bell. This is fair, sort of: virtually movies are, after all, wish-fulfillment fantasies of a sort when you dig down deep enough, though not typically for the people who make them at the exclusion of the people expected to pay money to watch them.

Anyway, Hit & Run is not really all that bad of a movie, and parts of it are extraordinarily charming: the parts involving Shepard and Bell, playing a bantering couple moving out to Los Angeles after dating for one year, so she can take a once-in-a-lifetime academic job. Not every real-life couple sparks onscreen chemistry; think of Elizabeth Taylor and Richard Burton, who were only credible together when they were screaming invective and humiliating each other in Who's Afraid of Virginia Woolf? But Shepard and Bell, happily, fall squarely on the "awesomely well-suited for each other" side of things, soundly replacing Andrew Garfield and Emma Stone in The Amazing Spider-Man as the most appealing real-world onscreen couple of 2012, insofar as that is an actual race. When they talk about insane, inside-joke bullshit, edged with meanness and full of raging lust and playful affection, it feels incredibly right, and real, and charming; indeed, though I'd have given just about anything for someone other than Shepard to have played this character, it's impossible to imagine someone with better chemistry with Bell.

Once you get past those parts, okay, Hit & Run sort of sucks. The film is about Charlie Bronson (Shepard), cooling his heels in a podunk town (in, I think, California, but it could also be somewhere in the Southwest), having entered the Witness Protection Program (thus explaining the forced tough-guy name). Here he has met overqualified college professor Annie (Bell), who has been invited to go to UCLA to build a major program in conflict resolution - and, if the movie did nothing else right, I'd have to tip my hat for whipping something so inordinately quirky as a girlfriend with a Ph.D. in conflict avoidance, and then actually making that a consistently important part of her character, and a significant plot point at numerous moments throughout the film - which is super-awkward, since Los Angeles is the one town in the whole world where Charlie absoutely really cannot go, since that's where the man he unsuccessfully testified against, Alex Dimitri (Bradley Cooper), roams the streets free, with a massive chip on his shoulder almost as prominent as his ridiculous white guy dreadlocks. But True Love trumps physical self-preservation, which is why Charlie and Annie are soon on their way in Charlie's idiotically recognisable classic muscle car, pursued by his short-tempered, nervous handler, U.S. Marshal Randy (Tom Arnold), Annie's psychopathic ex Gil (Michael Rosenbaum), sexually frustrated gay cop Terry (Jess Rowland), and a whole mess of angry gangbangers looking for Charlie's head.

The ensemble cast is generally pretty fine - Cooper makes the worst out of a character that's already more a bundle of clichés than actual personalities traits, but he is very much the weakest link - but that doesn't do much to save a film that feels sweet and likable whenever it's about the central romantic relationship and how the action-packed road race surrounding them metaphorically represents how difficult it can be to get over a lover's sordid past; whenever it's actually about a big ol' highway chase movie, with car stunts that required either a bigger budget or a better choreographer, with shoot-outs, and with embarrassingly mix-tapey rock stnadards underscoring every tiny bit of action (another '90s throwback), it feels threadbare and frankly, rather stupid: the low-fi approach to car stunts is refreshing, but Shepard and Palmer don't have enough talent to match their desire to make a rollicking action comedy, and there's really no getting around that fact. Shepard's script is knowingly hokey enough that the film's uncommon smallness of scale and ambition almost feel like they're there on purpose, sometimes, but too many of the big setpieces feel like kids goofing around on an abandoned stretch of road, knowing that they damn well better not actually damage the cars they've borrowed for the day.

With the action being pretty much a washout, the only thing left to save the movie is its value as a hang-out piece, and it comes close: the characters and actors are all mostly fun to watch, though they're all also insubstantial stock types, even the ones that aren't (to my knowledge "gay cop frustrated because there are no other gay men in his hick town" is not a stock type in this or most nearby universes, and yet it still, somehow, plays like it is). Other than the central couple, who are delightfully lived-in whether they're being terribly cute or terribly annoying - and there are certainly moments where they're almost too annoying for words, including a horribly twee opening scene - everybody and everything feels like window dressing, and that makes for a movie with way too damn much stuffing, however easy-going it is throughout, and how gently pleasing it as at its not-infrequent best moments. It's the kind of film that, if you landed on it one night on basic cable, would be a pretty perfect way to waste some time, but with the extra pressure of watching it as a proper movie, where you have to pay attention and engage with it, it just barely falls short.