Tropic Thunder, Ben Stiller's first directorial effort since 2001's Zoolander, may ultimately feel a bit toothless—it's difficult to cut too deeply when your satirical take on studio blockbusters and crazy actors is produced by a major studio with Tom Cruise in a supporting role—but offers a number of genuine laughs between the self-congratulatory waves. It's just good enough to make you wish it were better.

The script by Stiller, Etan Cohen (King of the Hill, not The Big Lebowski), and Justin Theroux turns on a nifty high-concept hook: Megabudgeted war film goes explosively awry, leaving its washed-up action star (Stiller), fart-happy comic (Jack Black), and Australian ultra-Method actor (Robert Downey Jr.) lost in the jungle with drug runners in pursuit. Such material should have been an easy bull's-eye for Stiller, who has previously (particularly in his self-titled early '90s MTV sketch show) displayed a genius for lacerating Hollywood narcissism. Here, though, he seems a bit off his game, ceding much of his onscreen time to the more manic, one-dimensional likes of Black, Matthew McConaughey, and Danny McBride. As for Downey's much-hyped blackface portrayal—well, he's brilliant, but, disappointingly, in exactly the way you'd expect him to be.

The first-act dead spots (how a scene between Steve Coogan and Nick Nolte can fall this flat is a genuine mystery) and general play-it-safe attitude are unlikely to keep this from becoming a huge hit—muddled as it is, Tropic Thunder delivers more solid laughs than any other movie this summer—but it's difficult not to wish for a little more genuine subversion and a little less inside baseball. Unleash Stiller's old cohorts Bob Odenkirk and Andy Dick on this material, and watch the studio suits shake for days.