Continuity: When the Mandrakises were about to leave for dinner, Dr Mandrakis opens the door then goes back to activate the alarm system behind the door. In between shots, the door goes from open to closed magically.
Continuity: When Jill arrives at the house and Mrs. Mandrakis shows her the phone list on the refrigerator Rosa Ramirez is misspelled, it has extra letters about 10 minutes later Jill dials Rosa's number and then the correct spelling is shown.
Audio/visual unsynchronized: When the kids are running away from the stranger, we hear the girl screaming but her mouth isn't moving.
Continuity: When Jill is lying in the hospital bed a pink balloon pops. In the next scene where it shows the floor, there is no popped balloon there.
Continuity: When Jill is running back from the guest house, before dropping the flashlight, you see a straight, continuous beam of light in front of her however, when the camera angle changes, it reveals her flashlight bobbing up and down as she pumps her arms to run.
Miscellaneous: When the alarm goes off, security calls to see if everything is alright. But when Jill comes running inside, the alarm goes off, but security does not call.
Continuity: While in the pond under the walking bridge, Jill's bangs go from pushed to the side to down in her eyes, to pushed to the side with no obvious reason for the movement.
Miscellaneous: When Jill calls 911 the second time, she is not redirected from the central to the local police station as she was the first time she called.
Continuity: When Jill's friend leaves the Mandrakis' house after sneaking in through the garage, Jill sets the alarm. Then later she opens and closes the door repeatedly without making the alarm go off.
Miscellaneous: About mid-way through the picture, Jill calls her friend at the bonfire, but the static on the cellphone is nothing like the sounds one would expect from a real cell phone, when reception is poor. Also, the intercept she receives in subsequent attempts to call her friend, includes, initially, chimes initiated by the old Bell system decades ago for land line phones. Cell phone companies don't use those chimes, nor do they use the wording used in this movie. The recording wouldn't say: "I'm sorry, the person you're trying to reach is out of range," not since the nineties anyway.
Continuity: In the shot where Tiffany is talking to Jill in the kitchen, her hair is slightly tucked on her right side. When the shot returns back to her seconds later, her hair is perfect and not tucked at all.
Continuity: When escaping, Tiffany gets into a Toyota Matrix. Yet when she goes to lock the doors, the locks are not of Toyota make.
Continuity: When Jill discovers her friend's body on the bathroom floor, the friend's left arm is draped over her torso. The camera cuts to Jill reacting, then cuts to an aerial shot of the bathroom as Jill runs out, showing the friend's body on the floor, with her left arm resting alongside her body.
Continuity: After Jill sees her friends body on bathroom floor, she slides down the shower curtain sliding it to a folded state. When she gets back up to run out of the room, the shower curtain is in the exact position it was in before she pushed it aside.