All animation in the film was done the old fashioned way: hundreds of pieces of paper with slight differences shot for three seconds then sped up in editing.
There is a gap in filming of almost six months between when Albert closes the door and Rachel and when he says "Holy Crap."
A mattress was places out of frame for the scene where Albert throws himself out of the house. On the last take the actor slid off the mattress and landed hard on the concrete beyond.
Both dogs appearing in the film belong to the actor playing Albert.