When Catherine initially stabs Mathew, she stabs him on his left side, the blade is horizontal. After the cut, the blade is vertical sticking out of the center of Mathew's upper back.
When Matt first meets the gunfighter he tells him to keep his hands up. As the shots cut from each perspective his hands go up and down several times.
Clayton and Catherine are eating dinner in a hotel dining room. Clayton tells her that he is a gunfighter and she is a woman between husbands. The shot returns to Catherine who is sitting in a different setting (her hotel room), but answers as if the conversation was continuous.
When Catherine hits Mathew over the head with the rolling pin, the rolling pin bends in the middle showing it to be made of rubber.
After the Sebaneks "rescued" Catherine and were settling down for the night, Matthew tossed a white cup at Johnny, which bounced and landed by his left leg. Johnny then picked it up and sipped from it.
After Matthew had soundly beaten Catherine about the face and she meets up with Clayton, there is no bruising or marks on her face at all.