Filmanui landed "Multiverse" and was also required to include either a bird's eye or worm's eye shot.
The film needed a whisper, a gatekeeper and a sign, with the last two "open to interpretation", Müller said.
It had to be made between 7pm on August 12 and 7pm on August 14, with a minimum length of one minute and a maximum of five minutes.
After brainstorming for half an hour, Müller spent the next two writing a script.
"We met at Russell's flat in downtown Whanganui the next morning and got straight into it," Müller said.
"He has a cat and unfortunately a couple of us were allergic. The film was made to look like it was night time so we had to board up the windows and black everything out.
"Breathing was a bit of an issue. By the end of the day, it looked like people were going to keel over."
Penton was "on fire" throughout filming, Müller said.
The project was a family affair, with Müller's identical twin daughters making an appearance in the film and his wife organising props.