At around minute 56, when Hazel is talking to Ray in Grace's house, Grace and Ella are seen behind Ray's shoulder coming over, going around a table in the kitchen. The camera switches to Hazel and then back to Ray and Grace and Ella are seen again, coming over around the table.
When Father Price prays the "Our Father", he uses the Anglican version, with the non-Scriptural coda "For Thine is the kingdom, the power and the glory". No Catholic priest (especially one as old as Fr. Price) would do this.
When Hazel hugs her mother in the hospital bed, the "vitals monitor" behind them it shows that her cardiac rhythm is 70/20. She would probably be dead with this vitals.
At the end, the Vancouver PD is dispatched to some apparently remote point in BC. It doesn't make sense to have the Vancouver police well outside their jurisdiction.
When the police are trying to figure out possible phonetic sounds the mouths of dead victims might have been set to form, they could have easily called for someone with lip-reading skills.
While Wingate (Topher Grace) is checking on Tamera Lawrence in Quebec (who has just been murdered), Hazel (Susan Sarandon) is on the phone with Wingate in Dundas. But among the photos of the victims on the wall behind her, a photo Lawrence's face after death can be seen. At that moment, no one yet knows of Lawrence's fate.
When Hazel returns home to find her mum sleeping in her armchair, Hazel walks in, removes her coat and walks past a mirror on the wall and into the living room. In the mirror, just after Hazel walks past you can see what appears to be the shoulder and upper arm of someone wearing a dark blue shirt- presumably a member of the crew.
When Wingate is tailing the person in BC the license plate is from Ontario.
When Ben Wingate is following Jane Buck in what is supposedly British Columbia, the distinctive skyline of the Niagara Escarpment is seen in the background.
Early in the film, one of the cops refers to a distance as a number of "clicks" (Canadian term for kilometres). However, later in the film, distances are states in "miles".
When Wingate enters the trailer were Gabriel was, he almost throws up because of the stench in there. At the end when the 2 Vancouver cops enter the same trailer, they walk in normally, like there was never any odor.
Toward the end of the movie, a woman at the Catholic Church is being interviewed by the police about the last time she saw Peter. She responded that he was present at a "Sunday service" 3 months ago. A Catholic Church employee would have said that he was at Mass - not a Sunday Service.
In the game and movie of Clue, there's a character named Professor Plum, not Professor Plume as he is referred to in this movie.