WATCH: Director and producer of 'Unbroken' sequel reveal the movie's challenges and why it's needed

Producer Matt Baer had quite a challenge on his hands when it was time to put together a sequel to "Unbroken," the wildly popular movie about Olympic champion and World War II veteran Louis Zamperini's fight for survival in a Japanese prison camp.

The next chapters of Zamperini's life saw the war hero struggle with post-traumatic stress, alcoholism, and an inability to move on from his difficult past. It was more of a spiritual story.

That's part of the reason Baer brought on Harold Cronk to direct. Cronk directed both films in the "God's Not Dead" series, and was the perfect person to blend high quality filmmaking with deep Christian themes.

"In having a director of Harold’s ability, it allowed us to tell the story in a traditional way, meaning a good screenplay, good production design, and good vision from a filmmaker articulating a story that everyone can access," Baer said.

"We believe that the faith based audience is ready to see a movie that is of higher overall quality in every category, and we feel good that we’ve achieved that," he continued.

The movie, which like its predecessor is based on the book "Unbroken" by Laura Hillenbrand, tells a part of Zamperini's story that both Baer (who produced the first movie) and Cronk felt needed more attention than it was able to get in "Unbroken."

"It was an incredible process, and we just wanted to really pay tribute to Lou’s journey," Cronk said.

"Unbroken: Path to Redemption" opens in theaters nationwide on Friday.