Within the world of stand-up comedy, there is the idea that you have not "made it" until you've developed a film or television project. I'm not sure if the comedians who chase this notion are responding to a desire to explore their craft or to climb the power structures of their industry, but this trajectory persists. No matter the size of the venues you play or the number of specials you produce, there is a ceiling to success in stand-up comedy that can't be broken until you move into another medium.

That's too bad. There are few sensations more thrilling than the unadorned and perfectly constructed joke, delivered as if plucked from the air. Stand-up is about a series of these small payoffs, which can exist independent of one another. The connective tissue is laughter: this thing is funny, and so is this thing, the comedian argues.

Film relies more on an accumulation of details and sensations. Even if it doesn't operate according to traditional narrative structures, a film must be more than the sum of its parts--it must reach outside itself. This is why television is kinder to stand-ups; it is broken into discrete pieces with beginnings and ends.

Mike Birbiglia is very good at stand-up comedy. He is fluent in the structure and rhythm of a joke, and has a peculiar approach to each. He appears to stumble into epiphanies, mangling his words until he finds something funny inside. This self-deprecating style is a perfect device for getting the audience on your side. By exaggerating his clumsiness, he appeals to his audience's fear of embarrassment, and lets them know that, tonight, they will not be the biggest screw-ups in the room. They are safe.

Paradoxically, this sort of controlled idiocy requires a tremendous amount of confidence. Because manufactured incompetence is different from the real thing--which simply makes you squirm.

Birbiglia is not so confident behind a camera. His first film, Sleepwalk With Me, was about the early stages of his stand-up career and the collapse of a major relationship, and it succeeded because he had adapted the source material across multiple media, turning it into a theatrical production, book, and podcast episode. He knew the essential pieces, and how to mold the rest to the occasion. Birbiglia also had a device, fourth-wall-breaking narration, that allowed him to indulge his strengths as a stand-up. Still, you could tell he doesn't think in cinematic terms, of visual and sonic textures. He thinks in terms of narrative and structure. The medium doesn't matter. The story is flexible.

His second film, Don't Think Twice, has the same problem, but it doesn't have the luxury of a finely tuned story to prop it up. The film is about an improv comedy troupe that loses one of its members to a fictionalized stand-in for Saturday Night Live (called Weekend Live). The remaining members confront the limits of their ambitions. Are they as good as they thought they would be? When success is measured against a single, unreasonable standard, are you doomed to be dissatisfied?

Sound familiar? If Birbiglia isn't consciously reckoning with the narrow expectations for a successful comedian, there is something in him that longs for freedom from the confinements of the entertainment industry. He wants to tell, but cinema makes him show, and he is not one for showing.

In the absence of compelling cinematic ideas, Birbiglia imitates. Specifically, he employs hand-held cameras to signify spontaneity, but he doesn't trust them. Rather than let his camera roam, Birbiglia cuts early and often. He has a great reverence for invention, but never indulges it. He is beholden to his 90-minute runtime, even though the film's setting and the size of its ensemble demand patience. Characters are pushed to the side, given just enough time to make themselves useful in the film's quest for forward momentum.

When an old friend arrives to visit Birbiglia's character, Miles, there is the opportunity for the film to pause and let Miles take stock of his emotional health, to ask if his career in comedy has stunted his personal growth. His friend is used instead as a signpost, a device to signal that Miles does, in fact, have the capacity to change.

The film does this frequently, hinting at depth while instead bouncing across plot points. Beyond their professional lives, we don't know what makes these characters tick, and that's a problem when you're trying to create friction. We are told of personal histories and relationships, but we don't feel them. They exist as facts, not living entities.

At least the film gets the casting right. The two most talented performers, Gillian Jacobs and Keegan-Michael Key, are assigned the two most talented characters, Samantha and Jack, the troupe's stars who are given the opportunity to audition for Weekend Live. It's no wonder they're the film's central romantic couple; they can't help but set off sparks.

Each also suggests a rich interior life, which is important in a film that doesn't leave time for proper character development. They approach their auditions from opposite angles, and that tension--between ambition and contentment--never leaves them. Jacobs and Key are always at odds with themselves, and I longed for that dynamism when they weren't on screen.

Don't Think Twice isn't a failure of concept, but of nerve. It doesn't have the stomach--or patience--to sit and linger and let its performers make discoveries. Its subject matter is improvisation, but it won't improvise itself, won't adjust when a promising tangent arrives. As a comedian, Birbiglia lets himself flail until he hits on inspiration. As a filmmaker, he hasn't learned to trust himself. When he does, the inspiration will follow.