While watching Jack Black and Ben Stiller bang out Envy Friday night, I reached a frightening realization: Jack Black has three times the acting range of Ben Stiller. JB has played a rock’n roll obsessed loser (High Fidelity, School of Rock), a shallow womanizer (Shallow Hal), and now a naïve dreamer in Envy. On the other hand, Stiller has been playing Mr. Furious for at least a decade and shows no sign of stopping.

In Envy it’s more of the same from Stiller as he mucks around with yet another variation on his downtrodden character who gets really really angry when subjected to stress. This time around the catalyst is jealousy towards his best friend, who cashes in on the billion dollar idea Tim Dingman (Stiller) passes up. The idea is “Vapoorize” a magical chemical that when applied to pet feces causes it to instantaneously vanish into the netherworld.

Tim’s friend Nick (Jack Black) dreams up the idea and pitches it to him, but Tim dismisses it as just another of his friend’s crazy daydreams and refuses to invest. A few weeks’ later finds Nick and his wife (Amy Poehler) building a Neverland-like mansion across the street, complete with cantankerous carousel and beautiful white horse. Tim wakes up every day with his family, staring across the street at his friends’ unbelievable success and being slowly but surely eaten alive by incurable envy.

Nick never intentionally flaunts his wealth in front of his neighbor. He builds a mansion across the street out of a genuine desire to live next door to his best friends and openly shares everything he has with them. But there’s laughter to be had in watching Tim die a little inside every time Nick feeds his kids flan or invites the Dingman’s over for dinner where Tim’s kid is forced to play a garbage can while Nick’s plays a concert piano.

Chris Walken is in the movie too and succeeds as he always does in delivering a perfect performance that in some weird way draws humor through parodying himself. Here he plays a disturbed old bum who calls himself “The J-Man” and drives an outrageous monster truck. He’s always a sure thing and has been shining for decades in thankless supporting roles like this, garnering memorable chuckles in otherwise unmemorable films. When Stiller eventually has his inevitable moment of angry-man meltdown, it’s J-Man who steps in to provide inspiration, hatching a plot which proves fruitless other than as a welcome catalyst to keep Walken on camera.

So Envy has some funny, but maybe not enough. It’s best when Stiller is exploding, or Black is flaunting, or Walken is well, just being himself. The movie is funny because the cast is funny, with little credit to be given to the somewhat disjointed script by Steve Adams. Reportedly Larry David had some input into the script and to me that shows most in the great uncomfortable moments between Tim and Nick as Nick works mightily to bring kindness to his friend and Tim sits quietly imploding from regret and comedic jealousy.

Towards the end of the film Tim finally has one last outburst in which he reveals everything to his friend, a speech which Stiller delivers with the kind of enthusiasm and zest he has only recently rediscovered. It sticks with you not only because it feels so openly genuine, but because Stiller and Black actually seem to have some sort of chemistry together. It may actually have been one of Ben’s finest on screen moments, though regrettably no one will see it lost in an uneven and poorly watched film like Envy.

Director Barry Levinson just doesn’t seem to know how to let go, to free his film to the dark hearted euphoria of Stiller’s manic material lust. Something’s being held back, whether from inability to deliver or some unknown studio pressure. Sometimes it just isn’t there. Whatever the case, the story repeatedly drifts away from the things which work and gets mired down in the things that just don’t. Wouldn’t it have been great if the J-Man had stood up in the middle of the film and reminded Tim that he has nothing to be jealous of? After all, Tim Dingman’s wife is Rachel Weisz and Nick is stuck being married to Amy Poehler.