First time viewing did anybody else think there were two killers? Throughout the film I was certain there was two but when Roman popped up on his own at the end I was quite surprised. The main reason I thought there was two was during the scene where Sid was in "her" house in the studio, Roman was surprisingly quick during that, he'd be in one part of the house then jump out at Sid from a different corner as she runs outside.
Maybe they could go back to this in Scream 4.