Continuity mistake: When Leo comes into Grace's design workplace, he starts to put pieces of cloth on his shoulder. Between shots, before Grace takes the pieces of cloth off of him, they change position on his shoulder completely.
Continuity mistake: When Jack and Will are outside behind the hedges, stalking Kevin Bacon, Jack hands the binoculars over to Will. Will holds the binoculars with one hand in one shot, but in the next shot he has both hands on them.
Continuity mistake: When Kevin Bacon is talking to Will about the cardboard cutout, Kevin throws the cutout down and it lands flat on the floor. In later shots the cutout is now leaning up against the fireplace. Then, later, it completely vanishes.