During the shooting breaks most of the crew played the Cube Escape series. Luckily the developers were there to provide hints.
The bird that played Harvey had originally red tail feathers and had to have another parrot friend on set to help acting.
The night shoot was taken in February outside of Prague and the movie crew were very lucky with the weather. Exactly after the last take it started to snow.
The Paradox room was entirely built in a studio. The owners of the studio still have the large cabinet including the pots with organs.
The door was transported to the forest location and light conditions of the room where matched on site to create the seamless transition from room to forest.