From left, Alpa Chino (Brandon T. Jackson), Tugg Speedman (Ben Stiller) and Kirk Lazarus (Robert Downey Jr.) are war movie actors who get caught up in a real battle in the action comedy Tropic Thunder. (Merie Weismiller Wallace/DreamWorks Pictures)

Ben Stiller has been hit-and-miss in his last five, over-exposed years, but his new action-comedy, Tropic Thunder, suggests he’s hitting again. Tropic Thunder is very funny — it’s also gory, brash, bratty and a bit undisciplined, which is risky in a satirical movie that deals heavily in the “R word” (more on that later).

Stiller, who directs, stars and co-wrote the script with Etan Cohen and Justin Theroux, opens the film with footage of a dramatic military rescue. Filtering the action through Hollywood’s timeworn Vietnam images, Stiller plays with Apocalypse Now’s visions of helicopters suspended over a green carpet of trees, Platoon-inflected slow-mo sequences and a smidge of Rambo-style retribution. Just as the film seems to be reaching for some big existential truth, the camera pulls back and reveals the mundane mechanics of a movie set. The two lead actors are shown as narcissistic ninnies. They fret so much about “being in the moment” that a scorched-earth explosion costing $4 million goes off and the cameras aren’t even rolling.

Tropic Thunder’s cuttingly funny intro section — a series of made-up trailers and ads — establishes each actor’s backstory. Tugg Speedman (Stiller) is an action star whose signature Scorcher series is beginning to cool. He’s trying hard to “stretch” as the lead in a weighty war movie. Alpa Chino (stand-up comic Brandon T. Jackson) is a hip-hop star and urban entrepreneur who wants to extend his brand. He’s understandably irked to find that Tropic Thunder’s lead African-American role has already been snagged by an Aussie in blackface. Australian Method actor Kirk Lazarus (Robert Downey Jr.), who recently wowed critics with his portrayal of a gay monk (the faux-trailer suggests a kind of Brokeback Abbey), wants to take his Oscar-winning versatility to the next level. So Kirk undergoes a “controversial pigmentation alteration procedure” in order to play Tropic Thunder’s African-American platoon leader. Jeff Portnoy (Jack Black) is a damaged funnyman who’s made a fortune playing every single member of “America’s favourite obese family” in a comedy franchise built entirely on latex fat suits and fart jokes. Lately he’s become uninsurable — he’s got a teensy heroin problem — and he thinks he can prove himself by portraying a war medic.

John "Four Leaf" Tayback (Nick Nolte, centre) is a Vietnam vet whose experiences are the basis for an epic war film in Tropic Thunder. (Merie Weismiller Wallace/DreamWorks Pictures)

Since satire always needs a norm against which excess can be measured, the film has one semi-sensible thesp: rookie Kevin Sandusky (Jay Baruchel), who’s been cast as the war movie’s requisite kid with glasses.

Given the egos on set, frustrated director Damien Cockburn (Steve Coogan) decides there will be fewer hissy fits if his stars are dropped into the Vietnamese jungle and forced to man up. He wants to throw some F/X at them and film it all guerrilla-style. (“Dirty, gritty,” enthuses Damien, who can smell the Oscar noms.) But cast and crew get more authenticity than they bargained for when the five main actors end up stranded in the heavily fortified territory of a very real Asian heroin ring.

It’s fun to trace the script’s satirical sources. You can see Eddie Murphy here, Jim Carrey there, a bit of Russell Crowe, even some pre-rehab Robert Downey Jr. Stiller handles the fake showbiz mythologies and the parodies of infotainment shows with dead-on brilliance. But at some point, Tropic Thunder has to walk into the jungle and work as a meta-film, and this is where Stiller slackens just a little.

The laughs keep coming, thanks in part to some brief but indelible turns by the supporting cast, like Matthew McConaughey as Tugg’s unctuous agent and Nick Nolte as the Vietnam vet whose war story is the basis for the script. Looking a little like his infamous mug shot, Nolte drops cryptic, Brando-ish utterances, talking darkly of a place where “a man is measured by how many ears are hanging from his dog tags.” Tropic Thunder’s worst-kept surprise is Tom Cruise, who makes a movie-stealing appearance as a bald, fat, crass studio exec. In a story that spoofs the way stars try to salvage their careers, Cruise shrewdly rehabilitates his image by playing an extreme version of the super-aggressive control freak many moviegoers believe him to be in real life. In one key scene, Cruise uses the same scary, unblinking stare that made that Scientology video such a YouTube hit — but this time, he’s playing it for laughs.

Downey Jr. continues his own comeback with a smart performance that combines lunatic intensity with a buried awareness of Kirk’s absurdly stereotyped take on the black experience. The role’s potential for racist idiocy is cut by crisp comic counterpoint from Alpa, who tries to dig down to Kirk’s white Australian roots with constant references to baby-eating dingoes and Crocodile Dundee.

Stiller can be very funny, even though some of his best shtick has been dulled by over-use. Black, uncharacteristically for the bouncy-ball performer that he is, fades into the jungle foliage with an underwritten part and spends most of his screen time jonesing for heroin. (Downey Jr.’s character charitably suggests he has a touch of flu.)

Tugg Speedman and Kirk Lazarus wind up in a real battle. (Merie Weismiller Wallace/DreamWorks Pictures)

The action — half jokey, half wildly violent — is often flat-out hilarious. At one point, Tugg becomes separated from the group and experiences his very own Heart of Darkness moment. Meanwhile, Kirk, who brags that he doesn’t break character until they film the DVD commentary, keeps trying to “represent.”

Stiller wants to make a serious point about the way Hollywood proclaims overt messages of tolerance and understanding while running on its own set of institutionalized prejudices. But his satirical method – he both uses clichés and critiques them – is tricky. Sometimes, the film’s humour becomes self-satisfied.

Take the music. Stiller spoofs the use of obvious period songs with his heavy-handed insertions of CCR and Steppenwolf. But whatever his intent, he ends up with a lot of soundtrack-friendly tunes. This paradox becomes more fraught in one of the movies-within-the-movie, a misbegotten piece of Oscar bait that stars Tugg as Simple Jack, a mentally challenged farmhand. In their discussion of this monumental flop, Tugg and Kirk keep throwing around the word “retard,” which has led to protests from U.S. groups that advocate for the disabled. “Never go full retard,” Kirk advises, shaking his head. According to Kirk, Hollywood adores developmentally challenged characters, but only up to a point. (Tom Hanks in Forrest Gump — yes. Dustin Hoffman in Rain Man — yes. But Sean Penn in I Am Sam — no.) Stiller and crew are making fun of actors who exploit “disability drag” to further their careers, but they don’t mind getting some cheap laughs out of the Simple Jack sequences, which are lazy when they need to be edgy.

Tropic Thunder is a good comedy, but it could have been great if the filmmakers were more willing to cop to their own complicity. Stiller’s satire lacks the queasy self-loathing that makes the best contemporary comedy about showbiz excess – like Ricky Gervais’s TV show Extras and some of Steve Coogan’s work – so uncomfortable. Tropic Thunder skewers Hollywood’s worst tendencies, but can’t help softening the attack with a wink that says, “Hey, we get it.” After all, even Tom Cruise is in on this joke.

Tropic Thunder opens on Wednesday, Aug. 13.

Alison Gillmor is a Winnipeg-based writer.