When it came time to work with Carrie-Anne Moss, an unexpected dynamic occurred on set between her and the lead Adelaide Clemens. At base camp, Moss was pleasant in her conversations with Clemens, but once they both arrived on set, Moss changed. As Adelaide Clemens describes, "She ceased any contact and kept a two meter distance from me. I did not fully realize this distancing until we started shooting; she came over and put her hand on my chin and I've never felt a more intense invasion of personal space. I just shuddered. It was fascinating and powerful."
Roger Avary was originally set to write the film and had actually begun writing a draft when he was sent to jail for gross vehicular manslaughter and two felony counts of causing bodily injury while intoxicated. The film was then delayed until the studio hired Michael J. Bassett in Fall 2010 to write and direct.
In the school corridor in the trailer, just after Heather bumps into Vincent, on the wall behind them is a poster for a graphics class with a picture of a girl with a butterfly/moth over her face. Moths/butterflies are used often as imagery in the video games and represent Sharon's "change" into Heather.
The last scene of the movie when Heather and Vincent are leaving Silent Hill, the truck driver who pick them up is Travis, who is the main character of Silent Hill: Origins, a prequel game. Also the bus with two police car escorting is tribute to another Silent Hill game, Silent Hill: Downpour.
In one draft the FBI-agents actually caught Heather but where killed when the police station turned into the Otherworld. In the same draft the Missionary was Claudia's henchman rather than Claudia. Red Pyramid killed it with it's bare hands rather than through decapitation and Claudia was stabbed to death. After killing Claudia and the Missionary Heather tell Red Pyramid that he is free and Red Pyramid would crumble to dust. Dahlia also died at the end and when Heather removed the seal from Leonard he did not die but simply turned back into a blind old man again.