Ballroom 20 was packed as director Luke Sparke hit the stage with Ryan Kwanten, Tricia Helfer, Nick Wechsler, and Jeremy Piven, joined by moderator Brandon Davis, to talk Primitive War, an independent Australian film that pits Vietnam War soldiers against dinosaurs. Seeing it on one of Comic-Con’s biggest stages was a rare sight for an indie.

Based on Ethan Pettus’ novel, the film follows Vulture Squad in 1968 as they’re sent to track down missing Green Berets. Instead, they find a remote valley crawling with prehistoric predators. It’s part war movie, part creature feature. “Primitive War” stomps into theaters in Australia and the U.S. on August 21.

Sparke, who also wrote and edited the film, said the story had to feel real before the dinosaurs showed up. The cast trained together and filmed in rough Australian locations to sell that grit. Kwanten admitted he picked a Southern accent before reading the script. Helfer got a laugh with a quick Battlestar Galactica reference, and Piven praised Sparke’s go-it-alone style, joking, “this movie costs $11, and it’s all his imagination.”

Fans got a look at new footage showing tense recon missions, chaotic firefights, and plenty of dinosaur chaos. It ended with the line: “This ain’t no walk in the park,” which got a knowing laugh from the crowd.

With millions of trailer views already, Primitive War is shaping up to be one of the most talked-about dino movie.