Continuity mistake: Near the end, when Scotty is driving Judy to the Mission, the view from inside the car of the road shows that Scotty is driving on the left-hand side when he should legally be on the right. It is not a one-way road, and it appears that the shot was flipped.
Factual error: The film begins in 1860, but the majority takes place 20 years later, so 1880. When James Rankin obtains files on the Haymarket Strangler/Edward Styles case we are shown another box labelled with details about Jack the Ripper, who wasn't active until 1888.