The Incredible Jessica James has just about everything you’d expect to find in a standard Sundance comedy: an aspiring writer, a blossoming romance, a beleaguering breakup, an eclectic collection of quirky friends and nemeses, and a rendition of New York City as the be-all and end-all of artistic expression. But The Incredible Jessica James has one thing that no other entry of its ilk can claim, and she’s just enough to keep the film from feeling like just another trip to the same old well.

Jessica Williams is not just the star of Jim Strouse’s latest picture, she’s its very life force. From moment one, Williams establishes her fictionalized namesake as some mystical hybrid of the relatable New York neurotic and an un-one-up-able cartoon character. Appropriately, Williams’ Jessica James describes herself midway through the movie as a unicorn, asserting to a newfound gentleman friend and the audience alike that we wouldn’t be so likely to find another character quite like her out in the wild.

Even as The Incredible Jessica James bounces between familiar set pieces—our heroine, a yet-unpublished playwright, struggles with unmet creative ambitions, all the while compromising lingering feelings for both an ex-boyfriend (LaKeith Stanfield) and a new fix-up (Chris O’Dowd)—Williams herself stays evenly invigorating. She strikes down the double-talk of lackluster blind dates with great fury, upends the politesse of a family get-together with rants about “the system,” and navigates her own fantasies and nightmares with humanity and lunacy both in ample supply.

Beside Williams, Strouse packs his film with an array of charming performers, notably O’Dowd as Jessica’s haplessly earnest new love interest and Noël Wells as her best friend at the constant ready. Still, many of Strouse’s supporting characters are regrettably underwritten; the latter, for instance, is saved only by Wells’ electric screen presence, relegated by the script to exposition and the odd well-intended joke about her sexual orientation.

Whenever the camera commits to someone or thing other than Jessica James, the film flounders. In truth, the script is not quite strong enough to sustain momentum when the ordinarily dialed-up-to-11 Jessica tempers down in the interest of what are meant to be some of the story’s softer moments. The movie’s most damning problem is also its strangest: Strouse’s film doesn’t seem armed with an acute understanding of a Jessica James’ function in the world of today. Where we may be inclined to celebrate her unrelenting chutzpah, The Incredible Jessica James demands she relent, bound perhaps only to the tradition of the many films from which it borrows its form.

We’re lucky, though, that The Incredible Jessica James has enough trust in its main character and star to let her run amok throughout the bulk of its runtime. Williams flaunts her dynamism in all corners of the world onscreen: the romantic, the creative, the professional, the familial, he psychological—in just about every corner of this character’s little world, we do see her flash her wily, kooky, stunningly inimitable brights. Whenever she’s asked to dim them, the seams peer through, and we see the film aching to commit to the Sundance comedy form that we know so well. But why go for same old same old when you’ve got someone as magnificently unique as Jessica Williams in the spotlight?

Rating: 3 out of 5

Images: Sundance Film Festival

Jessica Williams and Noel Wells on why online dating sucks:

Michael Arbeiter is the East Coast Editor of Nerdist. Find him on Twitter @MichaelArbeiter.