When Jason places the "bride" victim on the bed near the beginning of the film, in close-up her eyes are gazing straight up and her mouth is slightly open. But, in the next shot, her gaze is lower and her mouth is practically closed. Also, the pillows around her head change.
At the police department, on the door to room 112 it states it is the Exhibits Room, but in the hall outside, room 112 is indicated as the District Attorney's office.
During the "wedding" at the beginning of the film, a cat is sitting in front of a player piano. When the music finishes, the paper roll rewinds and stops. In the last two shots of the cat, the paper roll on the piano behind it changes positions.
Jason is able to shoot Sgt. Albertson using a gun placement in his stub, though it doesn't appear that he could've been able to pull the trigger. It's likely he has a string on the trigger that goes through his coat and is attracted to his other hand that made the trigger pull. (as it's common for people with stubs that use prosthetics).
At approx. the 13:53 mark, the torch reveals that the footage has been racked forward and backward to pad out the time needed for the verbal description of the crime.