Jess, in her dream, sees a lady that cut's her throat and says, 'Przepraszam'. The Polish word meaning 'I'm sorry'.
The majority, if not all of this production was shot in Wales in the UK and particularly the capital, Cardiff.
Everyone who knocks on a door in this movie, knocks twice.
Don't Knock Twice is the basis for a video game - Don't Knock Twice (2017) which was released in 2017 for Microsoft Windows, PlayStation 4, Xbox One and Nintendo Switch, sharing a loosely similar story as the film.
Baba Yaga, the demon featured in the film, is also the nickname of actor Keanu Reeves used in the John Wick movie franchise.
