Continuity mistake: Gale's bangs change lengths throughout the film.

Continuity mistake: When Sarah tries to fix Roman's statue's head, her hair is over her face, when she goes to answer the phone her hair is pulled back behind her ear. (00:23:20)
Continuity mistake: In the scene where Jennifer gets killed and falls through the mirror look at Dewey's hair it's all messed up, but in the scene right after that when Dewey and Gale are looking for Tyson his hair's all combed back again.
Continuity mistake: Gale and the killer go flying through the basement door, you see the door opens out, but when they crash through it, it opens in. Its not a two way swinging door, because you see the hinge at the top of the door to open it out, not in.
amycamille1975Continuity mistake: Dewey rolls down a hill after shooting at the killer. The cut on his forehead changes shape from circular to two parallel lines then to a straight line and a waved one.
Continuity mistake: In the opening scene Christine is completely dry when she steps out of the shower.
Jacob La CourContinuity mistake: At the part where Sidney is on the set of her house and the killer is chasing her up the stairs, she runs right by the plants, but in the next take she is right next to the plants just about to throw one.

Continuity mistake: Before Sidney pulls the killer out of the door on the house set, we see the bedside table is lengthwise against the wall. As the killer falls towards the bed it's turns 90 degrees, so the bed is a bit closer to the door.
Jon Sandys
Continuity mistake: Roman's sideburns change lengths towards the end of the movie.
amycamille1975Continuity mistake: At the end of the movie when Sidney is lying on the floor, Roman is pointing the gun to her head about to kill her. The gun is clearly pointing to her head/neck area when he shoots, but Sidney still lives and shows him she was wearing the vest. The vest protects her chest and Roman shot her in the head.
Continuity mistake: In the scene where Dewey and Gale are having lunch, Dewey asks her "Why would the police come to you?" In the background, a waitress in white walks by. Then they switch to Gale and the waitress has vanished.
Answer: Those are misdirects/red-herrings to make you suspect Kincaid. Not actual pieces of evidence. But Roman is confirmed to be the only killer in the film. Originally, there was going to be a second killer (as there is in the three other films), but the idea was dropped during production to change-up the formula slightly and keep audiences guessing.
So how could Roman call her in that moment?