The boulder was made of fiberglass. A large net was kept open on the ledge of the pool so that if the boulder went over the pool, it would not continue down the hill into the village below. Additional shots involving the boulder were created digitally.
The conversation in the kitchen between Gal and Don originally took place in the living room, but the director decided that a more domestic and less formal setting would be more effective. Also, the shot where Don kicks the cabinet doors was done in only one take; the director decided that coverage wasn't necessary.
When the rock rolls down the hill and almost hits Gal, we see it passing at his right side. But when the rock falls in the pool, it's clearly at his left side.
(at around 7 mins) When the camera pans to the left from Gal with his arms in the air on the sofa outside; to Aitch dancing, a hand is briefly seen in front of it.
Don: I fucked Jackie. Dirty cow. During what we were doing, she tried to stick her finger up my bum. I nearly hit the roof, you can imagine. I mean, what have you got to think of a woman who'd want to do that?