Matthew Heineman’s much anticipated documentary feature City of Ghosts celebrated its premiere last week at the Tribeca Film Festival.

Heineman’s documentary Cartel Land was celebrated across the festival circuit, award shows, and beyond, earning an Oscar nomination and Cinematography and Directing honors at the Sundance Film Festival where it premiered. The film was praised for Heineman’s in-depth, embedded approach to covering the cartels and the vigilantes who are fighting them along the Mexican-American border.

Staying true to that hands-on method that drove Cartel Land, Heineman is back with City of Ghosts, a documentary covering Raqqa Is Being Slaughtered Silently (RBSS), an organization of Syrian opposition journalists. The Playlist deemed the film, “a wide-eyed jaw dropping look at the battle against ISIS,” citing that the director “has a unique ability to condense and explain complicated information and political events without straying from the deeply personal journey of his subjects or relying on talking heads or text… Heineman doesn’t sugar coat anything at all. This is the truth about what is happening in Syria, and we should be shocked, dismayed and horrified.”

In Slant Magazine’s review, they note the affecting power of the film. “More than just a tribute to RBSS’s bravery, City of Ghosts works as a sobering and, in its own way, inspiring look at the sacrifices they’re making – to their lives, to their well-being – in order to bring the world the truth about life in Syria under the ISIS regime.”