To stay true to the story, the director didn't want the actors to meet or rehearse together before filming. The moment the hoods come off in the film is the first time they see each other in real life as well.
The only rehearsal that took place was between the director and the actors individually.
The table was specially designed for the film and took about three weeks to build.
It's never revealed how many members from the "resistance" are actually in the room during the game.
The screenplay took about three months to write. The 12th draft became the final draft.