While the latest attempt to bring At the Mountains of Madness to the silver screen hasn’t come to fruition, that doesn’t mean director Guillermo del Toro has given up on the project.

“Mountains of Madness has been with me for 13, 14 years and I really don’t want to give up on it,” del Toro tells the LA Times. “Look, the movies I do, I stick with them when I think, well, if I don’t do it, nobody will. … Hellboy, if I hadn’t done it, I don’t think anyone would have. Pan’s Labyrinth, same thing. Mountains of Madness, the way I plan to do it is a very peculiar take, and I think if I don’t stick with it the version I would like to see would never get made.”

One reason cited for del Toro walking away from the latest attempt to bring the H.P. Lovecraft novel to life was a dispute over the rating for the film. The studio wanted a PG-13 version and del Toro wanted to shoot for an R-rated version.

“I’d rather address the budget than the rating,” he says. “The movie can perfectly someday be PG-13, but contractually I need to protect it. There’s nothing in the movie that is profanity or sexual situations or any of that. But what we learned with ‘Don’t Be Afraid of the Dark’ is that sometimes intensity, the intensity of the situations, garners you the R. Don’t Be Afraid of the Dark,in my mind, should be a PG-13. It’s several intense moments [that] got us the R — I think some of the situations at the end, I don’t want to spoil it, but there are a couple of moments at the end that they deemed were too intense and I didn’t want to water down the movie.”