'I Tonya' is a wonderfully entertaining burlesque of a biopic

Margot Robbie as Tonya Harding

It's probably a testament to how good I, Tonya is that when the narrative shifts to the infamous assault on ice skating icon Tonya Harding's rival Nancy Kerrigan it may be the least interesting part of the movie.

I, Tonya is not a particularly deep film. For instance, Allison Janney, who gives a knockout, hilarious, surefire Oscar nominated performance as Tonya's mother, is really just playing a one-note type rather than a fully fleshed out person, but when the note is played this beautifully, who am I to complain?

A movie about Tonya Harding could have been very, very bad and exploitative, but instead the filmmakers here make a concerted effort to totally humanize the stereotypically white trash, chain-smoking skater, so much so that audiences will likely leave the film totally re-evaluating their perceptions of her.

Still, wisely the movie is ultimately more interested in indicting the culture that created the Harding myth, rather than trying to litigate who did what and when.

The film, which is periodically broken up by direct-to-camera narration from Janney, Margot Robbie (in a breakthrough performance) as Harding and Sebastian Stan, as her justly maligned estranged husband Jeff Gillooly, offers various skewed, untrustworthy but amusing perspectives on the action -- which covers Harding's whirlwind rise and fall in a brisk two hours.

Even though calling out the 24-hour tabloid society we've become is nothing new, the movie's best moments tap into the pure absurdity of the obsession with the Harding story -- and when her story fades from the headlines only to be replaced by the O.J. Simpson saga, the film really justifies its existence.

What is revelatory are the performances in this film, which are fierce, funny and unpredictable. Only Janney could make a verbally and physically abusive mother a comic delight. She physically immerses herself in this role and although you never get a real sense of what makes her tick, she also never feels inauthentic, which is a real feat. In one late scene she almost seems to show glimmers of humanity -- and this moment is worth the price of admission.

Margot Robbie is a marvel. She looks nothing like Tonya Harding and labors a bit to capture the accent. But otherwise, Robbie gives such an open and emotional performance, in which every slight and wound can be felt, and which also shows some of of the caustic edge that made Harding great on ice and not so great off it.

Meanwhile, Stan, who is likely to be overshadowed in the awards season race to the showier Robbie and Janney, is actually a quiet marvel in this movie. His Gillooly is a violent, pathetic, none-too-bright man, but he is also weirdly watchable and even somehow a little sympathetic, emphasis on a little.

A film like Foxcatcher did a better job of portraying an obsession with a particularly peculiar sport than this film does. Tonya's skating is just a matter of fact, we never really understand why she loves it other than that it may be the one thing she's good at -- but this is not a film about sports or even competitive drive. It's a burlesque show, it's a circus -- and a wildly entertaining one.