Continuity mistake: When Alex and Lucy are sitting outside on the step at night, as Lucy tells Alex about her old boyfriend, her hands go from being down on the floor, to on her knees, to back on the floor, then back on her knees between shots.
Continuity mistake: When Lucy is in the pool, Richard arrives and Lucy swims to the side, putting her hand up on the side. It cuts and suddenly Lucy is back swimming in the middle of the pool, and then she swims over to the side again.