This film's runtime was cut from over an hour in length to 46 minutes. Director Scott Achord felt a story about the clash should not have as many side stories going on at the same time (such as Mycroft hunting down a separate killer, and Lestraud looking into Clay Kosinsky from Holmes 3). That way it simplifies the narrative so people can remain focused on the rival's facing off.
Award Winning musician Michael Kisur did the end credits song, Achord would hear Kisur's song Red Line at the grocery store all the time and was a fan of his work outside of there. One day Kisur responded with enthusiasm towards helping with the project. Two weeks later the end credits song was submitted to them.
Throughout pre-production Achord, Rodriguez, and Maldonado kept discussing the finale. Achord suggested a theatre due to the symbolism of filmmaking. They got ahold of the North Bend Theatre in Washington, one of the older more traditional theatres in the state. Filming there took a full day.
During the scene where Holmes and Watson rest on the door, in order to loosen up during one of the takes Rodriguez and Maldonado did a duet of The Way You Make Me Feel in character. Moments after, they shot the take that would be used in the film.
This film's story was originally scripted out before Holmes University 3 was completed. The idea was tossed around if they made just a trilogy what would be a solid ending point. Before the production of 3 they discussed continuing well beyond that point, the script was reworked multiple times to show longevity. The draft they decided upon was when Maldonado said that is the best thing you've written (to Achord).