During the scene where Nick and Sam come upon Richard having a midnight snack in the kitchen you can see a small bright whitish reflection of some kind of equipment in the top left (our left) kitchen window, down in the lower right corner. There is no character movement or other scene related explanation for this reflection. It moves and fades during the scene, most dramatically at the end of the scene.
A group of old college friends reunite at the funeral of Alex, another old college friend. The part of Alex, the corpse, who is only partially seen in the unusual opening credits with the undertaker, is played by Kevin Costner, in one of his first roles on film.