The "Hotel Argento" where the Collector has his victims is a nod to the cult Italian horror director Dario Argento.
The mannequins are a nod to the film "Maniac" (1980).
A sequel titled 'The Collected' was announced to be in development in May 2019. In October that year, production was mysteriously halted after only eight days of shoot and never progressed. As a result, several props from the shooting set was stolen. In 2021, screenwriters Marcus Dunstan and Patrick Melton confirmed that a sequel will not be happening due to creative disinterest between them and the producers. However, Dunstan and Melton shared some BTS photos of the abandoned project in May 2021.
The house owned by Elena and her father, is the same house belonging to the Yakavetta crime family shown in The Boondocks Saints 2.
When Brian is running from the thresher-like machine, he runs between Josh and a blonde Josh is kissing. This is the same blonde Brian was kissing when Elena spotted him, credited as actress Heather Mote.
John Gulager: (at around 17 mins) If you look closely at the police arresting Arkin in the hospital, one of them is horror director John Gulager who has collaborated with Marcus Dunstan on other films.