In 1987, Shane Black sold a script called Lethal Weapon. He was 26. Over the next ten years, he changed the way scripts were sold and, more importantly, the way action films were made. At the peak of his career, he was the highest-paid screenwriter in Hollywood, earning $4 million for writing The Long Kiss Goodnight. But that film flopped, as did Black's The Last Action Hero, and Black all but vanished for most of a decade. Kiss Kiss Bang Bang – inspired by James Bond, Pauline Kael and everything in between – is his comeback film, and as comebacks go, it's a great one. A splashy (and, admittedly, sometimes trashy) genre hybrid, it's a Big Movie that often feels like a little one, a factory-produced spectacle covered in auteur fingerprints.

Black's directorial debut announces itself right away as a fractured fairy tale. Its score is pure Disneyland noir (imagine The Matterhorn hijacked by Mickey Spillane), and its incredible credit sequence unfolds like picture book, sprinkled with ink-blot blood and lipstick smears. Bang takes place in a sunshine-and-noir version of Los Angeles that we haven't seen on screen in a while. It's never looked quite like this; Bang's Technicolor renders foliage turquoise, and moonglow streetlight-amber, something akin to optical piss. It borrow heavily from everything from L.A. Story to Alphaville (and surely whatever's in between), but never shamelessly or without charm. At its best, Kiss Kiss is an homage to the art of paying homage. Quentin Tarantino is fond of talking about the chore of having to brush the Shane Black dust off his shoulders, but within the first few minutes of Kiss Kiss Bang Bang, you get the feeling that Shane Black might've looked at Tarantino's mid-90s output, and felt compelled to stay out of the business until he could raise his own game. Pulp Fiction was supposed to change the action genre, to liberate it from the rut that films like Black's had inadvertently created. But this is the first picture I've seen to really take what Tarantino's films managed to do with the genre and move it to another level.

What little plot there is concerns a petty thief named Harry Lockhart, played by a brilliantly self-effacing Robert Downey, Jr. Chased off a job by cops, Lockhart bumbles into a casting session, and in the blink of an eye, he's in L.A., preparing for a big audition for a role in a detective movie. The producer of the film tells Harry to hook up with an actual detective/movie consultant (because, as we learn, every detective works two jobs) nicknamed Gay Perry (played, with a nice feel for double entendre, byVal Kilmer). Not unpredictably, it's not long before various blondes start dying, and the fake detective finds himself on a real case. If it sounds cliche, that's only because it is. Anyone hungry for a rigorously inventive (or consistently scrutable) plot would be advised to look elsewhere; Kiss Kiss Bang Bang is an unabashed exercise in feeling and style, and its various story contortions almost beg to be dismissed as mere racks on which endlessly entertaining spectacle necessarily hangs. This is less of a problem than you might imagine; all that excess is actually infectious.

It's an incredibly talky picture. The first half of the story is told through dense narration, which Downey delivers at often-breakneck speed. It's heavily expository, but also Godardian – which is to say, fractured, full of digression, and extremely unreliable. When Downey introduces himself by saying, "My name is Harry Lockhart, and I'll be your narrator," he says it exactly as though he were taking your order at Red Lobster. The genius of KKBB is that it creates a context within which this is not an uninspired inflection – it is, in fact, exactly what the line needs. Over and over again, Black and (especially) Downey breathe unexpected life into old tricks.

Harry is the kind of guy who gets an A+ in talking shit, and a C- in backing that shit up. After attempting to exercise chivalry over a drunken dame, he gets his ass kicked surrounded by fake mini-Christmas trees. That drunken dame turns out to be his childhood anti-sweetheart (he loved her; she slept with every guy in school except for him and possibly his best friend), the improbably named Harmony Faith Lane. Harmony, played by Michelle Monaghan, always seems to have a red bra poking out of her poured-on dress. She drinks straight from the bottle, and she definitely sleeps around. Harry loves her not despite of her faults, but because of them, and Downey's eyes drip with extremely convincing puppy dog affection every time he looks at her. Harmony is, allegedly, a washed-up non-actress, but Monaghan is far too young for the role, and her casting would be puzzling were she not so good. Despite their apparent twenty-year age gap, she and Downey have a chemistry that's both comfortable and exciting, and their sort-of romance feels real. It's infused with a very cinematic seesaw of banter and longing, but also a very familiar kind of mumbling insecurity. They both mess up; they both get over it. It works.

And not everything in this film does. Certain lines are simply awful (there's a dated reference to Drew Barrymore that threatens to stop the whole thing cold), and at other points, the film is simply not as clever as it thinks it is, which may be a worse offense. But overall there's something terribly admirable in the way Black takes apart the action film and puts it back together with a decidedly personal touch. There's a humanity here that we don't see much in such jokey shoot-em-ups. Harry takes death seriously – when he has to kill, it almost kills him. Downey is the perfect actor for the part: he's always had a bit of an angel of death thing to him, but Black really drags it out. There's a scene here where he watches a woman get shot whilst hiding under her bed. When the corpse falls, Harry, visibly affected, reached out and presses his fingers to her lips. It's an amazing shot, and in it, you see vestiges of every ghost of Downey's past – from the real-life half-dead crackhead, back to Chaplin, and even back to the fake half-dead crackhead of Less Than Zero. Downey's way too good to have been off the A-list for this long; here's hoping Kiss Kiss (which, incedentally, begs for a sequel) brings him back.