Trivia

If you watch REC (2007), [Rec]² (2009) and this film back to back without watching the end credits, the three movies would play out as one entire sequence of events.

Most of the film was shot on an actual oil rig ship. Some of the sets had to be recreated from the ship at the studio in order to allow space to film and do stunts.

Tristana Medeiros (the possessed girl who started the outbreak) is the only character to appear in all four films.

Writer/director Jaume Balagueró and his work partner Paco Plaza have announced that there will not be a fifth installment to this series, even though this film was left open-ended.

This is the only installment of the franchise that's not filmed as found footage at all (only the beginning of [REC] 3: Genesis (2012) was filmed as found footage).