- Channel Hop: In the U.S. the rights to the first movie are owned by Sony via Screen Gems (who produced Quarantine and released this after the former hit DVD), while the rest are owned by Magnolia Pictures. Then in late 2018, got another release through Shout Factory, with all the movies.
- The Danza: Pablo Rosso plays Pablo in the first film and Rosso in the second. Both characters are cameramen (just like him).
- Deleted Scene:
- The interviews originally went for longer, showing the Asian couple (both) to be more fluent in Spanish, and César saying that he was a hairstylist and accusing Mari Carmen of being unfaithful to her husband.
- A long sequence in the first film had Pablo finding a wall in the attic that was completely covered in nails, foreshadowing the Medeiros girl using a hammer, and also three dead young boys. He would keep this secret and refuse to tell Ángela what he was seeing.
- Dyeing for Your Art: As soon as the chainsaw scene was scripted, the traditionally thin and frail-looking Dolera resolved (on her own) that she had to hit the gym and hire a personal trainer until she was muscular enough to make it believable.
- Enforced Method Acting:
- During the filming of the scene where Alex (the young fireman) falls from the stairs, not a single actor knew that was going to happen, so the reactions we see on the films were the real reactions of the actors themselves.
- They didn't know that Jennifer (the little girl) was going to be infected either, they thought she really was just sick.
- Manu didn't act as if he hurt his ankle. That actually happened during the filming, and he didn't stop.
- Image Source: Stairwell Chase
- What Could Have Been:
- The first idea was to set the story in a police station.
- The ground floor business was going to be a driving school before it was changed to a textile workshop.
- At one point, Balagueró and Plaza considered Mercedes Milá, the Spanish hostess of Big Brother, to star in the film. Just one year later, the UK kind of pulled off that joke with Dead Set.
- The monster in the attic was originally going to be the mutated Father Albelda, a.k.a. the man from Madrid. The creators came up with the Medeiros Girl after Botet was already cast to play him.
- During one of the takes of the scene where the handcuffed zombie tries to reach the other characters, the actress managed to jump over the railing and reach the stairs in one go.
- An early version had Leandro running after Jennifer and trying to inject her himself.
- Two alternate endings were shot, one where Ángela used the night vision to leave the attic and walk down the stairs to the outside, as the infected couldn't see her in the dark, and another were she was killed halfway by Mrs. Izquierdo. The first one was just intended to make Velasco believe that Ángela would survive the movie and scare her for real when Mrs. Izquierdo attacked, though (which angered Velasco).
- Related to that, the first attempt to film it failed because Velasco managed to run back into the attic and closed the door behind her, "saving" herself. So the writers had to step in and tell her that, no, Ángela was not going to escape the building.
- A deleted scene in [REC]2 showed the civilian intruders finding Álex as a bald and bloated zombie. Though still chained to the table and apparently calm, he would bite Jorge when he mistook his zombie moans for words and lowered his head to listen. In the final film, Álex is closer to his [REC] appearance, and Jorge is killed by Mari Carmen.
- Leandro's zombie appears in 2's making-of wandering freely around the building, but is not in the final film.
- It was agreed that the main character would be named after the first person who phoned the writer. This ended being Ángela Vidal, a friend of Paco Plaza's wife and future star of [REC]3, Leticia Dolera.
Trivia / [REC]