The filmmakers cite Steven Soderbergh's Out of Sight (1998) as a big inspiration for the energy and tone of the movie.
The entire movie was shot in one night.
The VFX team took inspiration from Luther (2010), True Detective (2014) & Kiss Kiss Bang Bang (2005) when creating the opening title sequence.
The director, Sam Bradford, actually voices the only other role within the movie as the night porter. The recording was then tweaked to make his voice almost unrecognizable.
The director's credit as the voice of the night porter was marked under an alias for fun during the end credits.
'Danny Ryan' is the combination of the two first names of the lead characters from Ocean's Eleven (2001) played by George Clooney & Brad Pitt.