Director Jon Harris had the crawlers slightly redesigned for this sequel. Apart from darker skin tones with better camouflage ability, they look more feral with more scars, and have more deformities to suggest years of inbreeding. Additionally, they have several rows of teeth like a shark, for ripping out flesh.
The original cast from the first movie returned to film for the video camera shots featured in this sequel. Executive producer Neil Marshall, who was the director of the first movie, wanted to flesh out the recording that Holly had made on her camera (in the first movie).
Production designer Simon Bowles took the script of this film and physically drew out a blueprint mapping how all 30 caves would connect together and how the actors would proceed through them.
There were 18 caves built for the first film, The Descent - Discesa nelle tenebre (2005), and 30 for this film.
Jon Harris was the editor of the first film, The Descent - Discesa nelle tenebre (2005). He returned as director and editor for The Descent: Part 2 (2009), which also marked his directorial debut. After this, he returned to his formal job as editor, this movie being his sole directing credit.