Huston's certainly right, but in the case of Gorilla the answer to your question is in the 5% left: the script. How did you cast this film and how lucky were you in the casting process? John Huston once said that 95% of the success of a film is in the casting. Gorilla is a comedy: how can you seduce a starlet when you look like a gorilla and you're treated like you are worthless? It's funny to me! But I'm convinced that it's possible to entertain with that, even if in some way this film is very personal. Having a guy trapped in heavy gorilla suit is perfect for that. In fact, I keep exploring the same subjects since my first short film: loneliness, lack of communication between people, and desire. Plus, my main ambition was never to show how serials or jungle movies were made - even if I like the idea of giving the feeling of being on a set of that time period, between the 1930's and the very beginning of the 1950's. Gorilla is not really an ape film, even though it's also a tribute to such movies. A story with a gorilla man as main character very soon came to my mind, because they were the guys nobody cared about, hard-working in really tough conditions and anonymous most of the time.
That website created by Chris Casteel is a goldmine with tons of amazing photos. Back In 2012, I discovered through the amazing careers of gorilla men like Bob Burns, Charles Gemora and Ray "Crash" Corrigan. I'm also a big fan of "behind the scenes" movies, like Singing in the Rain or Barton Fink. But this is something I forgot for years.
Well, as a kid or a teenager, I've always been fond of movies with apes: the original King Kong, The Planet of the Apes, Greystoke.