They say you can't go home again. Well, either "they" - whoever the hell "they" are - are talking complete bollocks, or maybe it's just that Kevin Smith is the exception that proves the rule. Either way, going "home" - to Leonardo, New Jersey, to the "View Askewniverse", and to two guys named Dante and Randal - has in fact turned out to be one of the best things that Smith could have done.

At first glance, Clerks II would appear to be the very epitome of an unnecessary sequel - the title alone conjures up images of such straight-to-video "classics" as Cruel Intentions 2, Starship Troopers 2 and - most hilariously - American Psycho 2. But then, that's probably because it's easy to underestimate the resonance that Dante Hicks and Randal Graves have had in the twelve years since Smith's moviemaking debut. Ignoring the ever-present and essentially one-joke (not that it's not a funny joke, mind) Jay and Silent Bob, these are the characters that we've really shared the "Askewniverse" with over the years. The original Clerks, after all, is just the tip of an iceberg that includes a short-lived but utterly brilliant animated series, a similarly short-lived but similarly brilliant comic book, a ten-minute short on The Tonight Show and a forthcoming animated movie. As a result, one of Clerks II's most startling effects is to surprise the viewer with just how much we care for these guys.

It means that as a step towards more emotional and mature work for Smith, it succeeds far more than the non-Askewniverse Jersey Girl, by giving us characters that are not only easier to identify with (smart-mouthed register-jockeys as opposed to widowed advertising executives), but whom we feel a genuine connection with from the opening scene. As an affectionate farewell to the Askewniverse, meanwhile (and, after earlier unfulfilled promises, this surely must be the last time Smith goes back to that world), it trumps Jay and Silent Bob Strike Back, by effectively bringing everything back full circle, closing on the guys who began it all, and giving us a satisfying and worthwhile conclusion to their story. There's barely a characteristic in-joke of the Julie Dwyer/Rick Derris/"thirty-seven?" kind to be had (save for notable cameo appearances from Ben Affleck and Jason Lee, and blink-and-you'll-miss-them ones from Smith regulars Joey Lauren Adams and Walt Flanagan), but Clerks II makes you realise that maybe, just maybe, they weren't the point after all.

Randal and Dante - Everymen for service drones everywhere

Don't think for a moment, though, that the emotional resonance of the film is borne solely of a newcomer-alienating affection for existing characters, though. There's something genuinely affecting about the manner in which Dante and Randal - two guys not exactly short of sharp wit and a modicum of intelligence - have found themselves trapped in the same jobs for so long, and how Randal in particular is left facing up to the idea of a life with absolutely no prospects, shorn of the one thing - his best friend - that previously allowed him to accept it. Dante, meanwhile, has at least found a way of extricating himself from his predicament, but is left to wonder if the escape to a new life, job and home in Florida is worth sacrificing friendships with both Randal, and his boss - the beautiful, kind-hearted, funny Becky - in favour of an almost subservient existence with an uptight fiance and her rich, overbearing family. Perhaps his plight is not one that many would necessarily identify with directly - but the simple fact of finding oneself at such a crossroads after reaching the wrong side of thirty is one that rings all too familiar.

Emotion aside, of course, it's the comedy that remains all-important, and while not a laugh-a-minute, raucous gag fest, Clerks II certainly doesn't disappoint in delivering Smith's trademark sharp dialogue and wit. The debate over the relative merits of the Star Wars and Lord of the Rings trilogies has already been quoted endlessly, but not without justification - if not quite the equal of the "Death Star contractors" conversation from the first film, it's still a hoot (in addition to casting further light on Randal as a man whom life simply left behind ten years back, clinging on to Star Wars in a world of Elf-fanatics). As for Jay and Silent Bob, meanwhile - the only other Askewniverse characters to return (if we don't count Flanagan's late cameo) - a reduced role, comparable to their very first appearance, suits them far better than being required to carry a film or a comic book, and almost every line that comes out of Jay's mouth is laugh-out-loud funny.

Of the new characters, Rosario Dawson's Becky is great - in fact, almost a little too great, if anything, right down to the familial sob story that sees her working in such a slummy job as managing at Mooby's. Movies always require a certain amount of suspension of disbelief, but the idea that this remarkable - and downright gorgeous - woman could fall for Dante is perhaps stretching it a little too far (despite Randal even commenting on the fact at one point). 19-year-old Christian uber-geek Elias, meanwhile, arrives courtesy of a superb performance by Trevor Fehrman, but the character is somewhat over the top in his weirdness - right down to the "pussy troll". Smith's world is at its best when the characters are real, and Elias isn't. It's O'Halloran and Anderson, though, that carry the film supremely. Neither of them will ever go down in history as particularly great actors - nor do they, Anderson in particular, give the impression of really wanting to - but crucially, they inhabit these characters perfectly. And if Randal was usurped as the Smith character all wisecracking comic book geeks wanted to be like by Jason Lee's Brodie Bruce in 1995's Mallrats, he proves himself here to be the far more sympathetic and enduring figure.

Some pictures just don't need "funny" captions

For someone whose films rely so strongly on comedic dialogue - and, in addition to the Trilogy debate, Randal's on top form, with misunderstandings about Anne Frank and reclamation of racial slurs two riffs that will leave audiences rolling in the aisles - Smith makes surprising use of set pieces in Clerks II. The infamous "donkey show" is a pretty funny scene, but is perhaps trying a little too hard to play for a movie-defining gross-out "moment", comparable to the implicit horror of Caitlin Bree's bathroom, ahem, "liaison" in the first film. However, brilliance comes from a rather more unexpected source in the shape of two segments both set to music and free of dialogue. The first, a go-karting sequence, gives a warm and fuzzy feeling at just the right moment, but it's trumped about two-thirds of the way through by perhaps the last thing you'd ever expect to see in a Kevin Smith film - an over-the-top, cheesy dance number. It should be absolutely hideous, but somehow, it's a wonderful, funny, life-affirmingly joyous piece of film - and Randal on the counter will surely go down as an instant classic moment among long-term Askew fans.

But is Smith just treading water by returning to comfortable turf after the mild flop that was Jersey Girl? Is he letting down his fans by going back on his original promise that the Askewniverse was over and done with? It's hard to say, just as it's hard to predict where he might go from here, given that he no longer has the safe fallback option that Clerks has proved to be. To be honest, though, such questions are irrelevant in the here and now, because what matters is that Smith has rounded on the detractors who said that a thirtysomething, millionaire Hollywood director wouldn't have the common touch to again write about the characters he originally plucked from his own experiences as a twentysomething, penniless convenience store clerk, and he's come out on top. In the process, he's produced a film that's, funnily enough, quite close in spirit to the first two American Pie films (and I genuinely don't mean to damn with faint praise there) - a superficially silly comedy with belly laughs and gross-outs that's not ashamed to throw in an emotional core, and not afraid to pose serious questions about what happens when one phase of your life comes to an end and you're confronted with the reality of having to finally grow up.

It may not be the masterwork that Clerks is - it's nowhere near as funny; in fact, it's nowhere near as funny as Mallrats, either - but it's a worthy companion piece, and it succeeds where Smith has so long just fallen short by adding genuine heart to the mix. With nary a "snootchie bootchies" in sight.