indieWIRE has a good interview with Duke and Charlie, focusing mainly on what it's like to film an adult stop-motion movie.
CK: I think so much of that finds its origin in the voice records that we did. It informed everything in terms of the puppet performances and so we got the actors and did this thing, which inspired us, and then went on to inspire everyone else working in production. They were all there, all the time, sitting in the recording studio together. It was pretty similar to the way the play was done but a lot more intimate setting without the theatrical presentation.
CK: The biggest thing that I came across, right off the bat, was that you can't shoot this like a regular movie with multiple takes. You have to, because it's such a protracted process, break it down to the frame and pretty much get one shot. And so not only do you have to make that work, you can't really start putting the thing together in any form because some of the shots are very short and obviously many of them take so long, you're waiting months and months and months before you can see if it's going to be working emotionally. And then to see the whole movie, you're pretty much waiting until the end of production. And the major lifting in terms of editing and all that stuff is done before you shoot the movie. That's an unusual way to work. (Source)