Continuity mistake: After the sheriff is killed Sam and Dewey leave to go to the hospital and it's daylight. On their drive to the hospital it's dark out. Then when they take Dewey's body out of the hospital and Gayle shows up it's suddenly light again.
Plot hole: Samantha has watched Stab, knows her father's story, and yet does not recognize she is entering Stu Macher's house. The cancelled Stab 3: Return to Woodsboro, seen in Scream 3, confirms Stu's house exterior looks exactly the same from the original Stab, and is being re-used as a prop for that film. (00:01:26)