Ben Stiller has been kicking around the idea for Tropic Thunder for nearly 20 years. It took a lot of time to get the script in fighting shape, but the time was well worth it. Tropic Thunder is tasteless and occasionally appalling but it is also wickedly, deliriously funny.

Set inside modern-day Vietnam, Hollywood is filming another epic war movie but this one’s in trouble. It’s over budget, behind schedule, and the first-time director (Steve Coogan) can’t control his actors. Tugg Speedman (Stiller) is a fading action star looking for another hit. Jeff Portnoy (Jack Black) is a crass comedian who’s after some real acting credibility. He’s also addicted to heroin and worries that people will only ever see him as a funny man who farts. Kirk Lazarus (Robert Downey Jr.) is a five-time Oscar-winning actor who, thanks to makeup and a lot of hubris, is playing the film’s African-American sergeant. Alpa Chino (Brandon T. Jackson) is a rapper breaking into acting and is steamed that the Hollywood producers gave the sizeable black role to a white guy.

The director is at his wit’s end and being bullied by producers back in America. He is advised by “Four Leaf” Tayback (Nick Nolte), the Vietnam vet whose story the film is based upon. Tayback says to get real emotion and real fear that the actors should be stranded in the jungle without their precious handlers and demands. So the director takes Speedman, Portnoy, Lazarus, Alpa, and newcomer Kevin Sandusky (Jay Baruchel) in a helicopter and out into the wild. Trouble is, the actors have been left in the middle of an actual drug war, except they think it’s all apart of the script.

Tropic Thunder is all things to all comedies. It could be tagged as being a bit incoherent but that’s because the movie has so much going on. It’s a sharp satire of Hollywood moviemaking and the raging egos of actors, it’s a send-up of Vietnam war movies and their bloody clichés, it’s a fairly worthwhile action film, and it’s a stupendously politically incorrect comedy with plenty of crude humor mixed side-by-side with genuine wit. It’s a comedy that has the potential to leave you aching from slapstick humor one second and biting satire the next. This feels like a complete comedy and not merely a series of sketches. Every character has an arc, some great moments, and each actor brings something different and something wonderful to the fray. This is clearly Stiller’s greatest achievement as a director.

The focus of Tropic Thunder is all over the place, and no one is safe from Stiller and his co-writers Etan Cohen and actor Justin Theroux. This is a brutal insider satire that plays it broad and loud. There are great jokes that ridicule the pomposity of the entire movie industry and the pitfalls of celebrity as a whole. I loved the jabs at celebrities going overseas and adopting children like they’re souvenirs. The movie has caught flak from disability groups that are mad about the movie’s liberal use of the term “retard.” I don’t want to say these people are missing the point of satire, or the fact that an R-rated comedy should offend on some level, but the joke is clearly on Hollywood and how movies exploit those with mental handicaps under the guise of telling their harrowing and inspiring stories. Movies have long been chronicling the adventurous lives of those with disabilities, which also has the side effect of making these people seem less like, well, just people. In the film, Speedman stared in a movie called “Simple Jack” about a mentally challenged boy who thinks he can talk with animals. Then the character has to pop up later in the film, complete with hysterical dialogue that blows apart just how exploitative these movies are (“I’ll see you in my head movies, but this is one head movie that makes my eyes rain”). It’s performed in just the right tone to make you laugh at the industry and the individual and not because of any disability.

The way the film establishes character back-story is genius. Tropic Thunder introduces all four major characters through fake commercials and trailers, like Grindhouse. The trailers are hilarious and a great way to kick off the movie. Stiller stars in a sinking action franchise where the world keeps being overtaken by fire (“Now, the one man who saved the world five straight times — will have to do it again”). The action franchise’s idea is to just reverse the scenario and, as sequels do, make everything bigger. Black’s trailer revolves around an obese family of super flatulent idiots all played by Black. The sequence is constant farting but it’s so over-the-top and pumped with contempt for lame-brained Hollywood comedies. The best trailer is the one that gives us Downey Jr.’s character, the esteemed Kirk Lazarus. Set in an Augustine monastery around the Middle Ages, Downey plays a monk who finds that he must conceal his inflamed passions for another man of the cloth (a figure I won’t spoil). Think of it as a 12th century Brokeback Mountain, and Stiller and company know exactly where to hammer Hollywood: the go-go eye stares, the hesitant naughtiness, and the ridiculous marketing angles – the title is inexplicably Satan’s Alley. The opening collection of fake trailers serves as perfect comedy bon mots for the feast that is to follow. They whet your appetite and may be the greatest opening 10 minutes of any comedy in memory.

Downey Jr. gives an unforgettable performance comprised of sheer brilliant comedic bliss. I loved every second he was onscreen and I fully expect the man to get an Oscar nomination for his work here. Now, the role of a Method actor playing a black actor naturally presents a tightrope that needs to be walked just the right manner to maintain a satiric tone that doesn’t turn ugly. Let me state clearly that blackface is never funny. It is repugnant and Hollywood has a rather depressing history with the unsavory practice (Gene Kelly and even Bing Crosby sadly did it). Tropic Thunder is not a Stepin Fetchit-style minstrel show where Downey makes eye-rolling racist stereotypes. The joke is not that Downey is playing a black man, the joke is that he is such an arrogant and egotistical actor that he thinks he can play anyone. Besides, Jackson chides him throughout the film for his unorthodox portrayal, which tells you where the filmmakers stand. Downey elevates every scene he steps into and gives a performance, like the film, that is densely layered with comedy. He never breaks character even when the cameras aren’t filming and even when he’s alone. He’s two steps removed; channeling a performance as a heralded Australian actor playing his idea of a 1970s black male. When Alpa derogatorily drops the N-word, Lazarus slaps him and then begins a speech with, “For over 400 years they have been using that word to keep us down,” and ends it reciting the lyrics to the theme song from The Jefferson’s. In that span of time, Downey takes you along on every stop in the dense, hilarious mind of Lazarus.

While the rest of the actors don’t ascend to Downey’s heights (years ago this would have doubled as a drug reference), the ensemble of Tropic Thunder works together smoothly and they help make the film so much more enjoyable. Black is great when he’s trying to be seen as a “serious” actor when they are filming. I love his rushed and hushed line deliveries. But he’s even funnier after going through the wringer of heroin withdrawal. A sight gag involving Black digging through his speedo had me in stitches. Stiller is playing his usual dimwitted blowhard but propels the plot forward. He knows exactly how to oversell for laughs, like when he’s being riddled with bullets in dramatic slow-mo or when he’s playing Simple Jack. Baruchel is a nice counter foil to the uncheck bravado and craziness of the other actors. Jackson has fun voicing his mounting vexation with Lazarus. Coogan and Nolte provide good small moments, and Danny McBride steals his scenes as a pyrotechnic special effects expert that wants to “make Mother Nature piss her pants.”

By now you’ve likely heard all about Tom Cruise’s small role in the movie as an irate, bald, fat, extremely hairy studio executive. It’s nice and amusing but I could have done with something different. Downey is unrecognizable in both physical appearance and through his speech; he fully inhabits a character that fully inhabits characters. Cruise, on the other hand, is instantly recognizable even with glasses, a paunch, and a shiny dome. It’s Tom Cruise playing a profane asshole but the joke wears thin. Cruise either needed to do something different or just be seen less, including his hip hop dance moves. And yet, Tropic Thunder has a running joke about Hollywood taking its beautiful A-listers and thinking that, through the power of makeup and superficial physicality, they can play any role. We’ve had a streak of Best Actress Oscar winners that have won accolades by stripping away their beauty and packing on the pounds (check out Charlize Theron in Monster). It seems like even the pretty girls are getting the ugly girl roles now; what’s a homely actress to do nowadays? So, in a way, Tropic Thunder is making fun of this line of thinking, that fat suits and some makeup are the great equalizer, but then it has Tom Cruise more or less falling into the same trap. He puts on a fat suit, a bald cap, but it’s still him and you hear Tom Cruise in every utterance. Maybe it would have been funnier if Cruise were playing a parody of himself since he is a studio executive at United Artists.

Tropic Thunder is a wildly funny movie that takes no prisoners when it comes to its sprawling satire. Stiller and company cut down the self-absorbed lifestyle and mentality inside the film industry and insecure actors. The film really shares the spotlight and each actor provides something different and welcome, and there isn’t a weak link in the bunch. Downey Jr. gives a brilliant comedic performance that will be long remembered. The movie is rude, crude, stupid, smart, and all over the place thanks to such a broad comic canvass. It took many years for Stiller to finally get Tropic Thunder off the ground but the wait was worth it. This is a rare comedy that eels loose, hits hard, and may warrant multiple viewings just to catch all the jokes-within-jokes. This is a movie with plenty on its mind, perhaps too much, but I wish more comedies were as well executed and skillful in their gags about gas passing.

Nate’s Grade: A