“Without an honest confrontation, there is no healing.” That’s from Birth Of A Nation director-producer-star Nate Parker today onstage at the Sundance Film Festival. In what I have to say was one of the most emotional experiences I’ve had at a movie theater, Parker world premiered what he called his seven-year “passion project.” His telling of the early 19th century slave revolt led by Nat Turner had audience members crying in their seats and jumping to their feet in a prolonged standing ovation at the film’s conclusion.

Potential buyers for the film streamed out of the lobby mere minutes after the cast had left the stage post-screening. Some worked multiple cell phones (with assistants standing nearby fielding calls of their own) in what appeared to be fevered discussions about the awards-bait film.

Speaking to the packed Eccles Theater crowd with almost the entire cast beside him after the lights came up, Parker said, “I made this movie for one reason only, creating change agents,” adding, “there are still a lot of injustices in our world.”

Related Story Sundance 2016: Titles That Have Buyer Attention

Sanitizing nothing, from the systematic and brutal torture inflicted by slave owners on the men and women they enslaved to the 48-hour bloody uprising led by Turner depicted in the movie, the film challenges our conceptions of that terrible time in American history and the lives it destroyed.

“These people thought they were doing good when they were doing bad,” said Parker of his effort to depict the entirety of the slavery ecosystem. “In 2016, that echoes,” he added, to a roar of approval from the Park City crowd.

While comparisons undoubtedly will be made to such films as Best Picture Oscar winner 12 Years A Slave, Parker’s movie has the added visceral impact of a movie like Schindler’s List, or a handful of other well-told films that depict genocide. So often, I wanted to look away at the carnage as the slave owners and their henchmen mutilated their slaves, but in fact I think that this film demands it be looked at with open and honest eyes. That is why the Sundance crowd reacted so strongly to the film Parker made.

For all the talk of Sundance becoming overly corporatized and perhaps losing sight of its indie mandate, watching a filmmaker put everything on the line on both sides of the camera is a reminder why there really is no festival quite like Sundance.