Other mistake: When Dr. Pincus looks at the three laxative bottles, there's a close-up of one of the bottles. The label on the bottle reads "Take 1 tablet daily with a glass of water" and "Qty: 50". Doesn't sound like a label for a liquid solution. (I noticed this in normal playback then paused to confirm it.) (00:09:10)
Revealing mistake: In the auditorium, when Tea Leoni is giving her speech about Pepe the mummy, Greg Kinnear (who is not visible to anyone but Ricky Gervais) starts yelling and Ricky Gervais gets up to walk away. As Greg Kinnear is yelling, an extra a few rows up turns to look at him. That shouldn't happen because the whole plot hinges on the fact that no one can see or hear these people besides Ricky Gervais.
Visible crew/equipment: Boom mic visible in several scenes, especially earlier scenes in the hospital and in the park.
Continuity mistake: When Dr. Pincus is in Gwen's apartment sitting on the chair next to the Great Dane, Gwen sits on the couch, opposite him. When Gwen sprays the air freshener she holds the can out as it heavily mists the air all around, in front of her. Yet in the shots facing Dr. Pincus, there are no droplets whatsoever in front of him. (00:52:45)
Continuity mistake: Having given Richard the nitrous oxide, Frank and Dr. Pincus pass three cars near the corner and they continue walking up the street. Those cars are visible in the distance behind Frank as he stands there wondering why he's still there, but in the next shot as he still stands there he is back beside those cars. (01:12:20)
Continuity mistake: When Dr. Pincus sits and stares at the three bottles of white Colyte solution, there is a close-up of one of the prescription labels with a red sticker underneath reading "warning: laxative agent". The red sticker is gone in all the other shots of the bottles. (00:08:35)
Continuity mistake: When Dr. Pincus pours the white Colyte solution from the bottle into his drinking glass, the liquid is about an inch from the top of the glass in the overhead shot, but next shot as he lifts the glass there is considerably less liquid in his glass. (The other MM mistake notes the level of liquid in the bottle.) (00:08:40)
Revealing mistake: When Dr. Pincus exits the hospital, as he approaches the brick walls, the shadow of the "ghost" nurse is seen in the sunlight on the ground as she gets into position at the edge of the right wall. You can also see her movement getting into position as she comes into the view of the camera. (00:13:45)
Revealing mistake: When all the ghosts wake up Dr. Pincus, he goes to the elevator where there are more ghosts, and in the shot facing Dr. Pincus the ghosts do not have a reflection in the mirror behind him. Odd though that they have reflections in windows - such as when the naked guy sneaks into Dr. Pincus's bedroom, countertops - such as when Frank sits at the bar counter with him, etc. (00:27:05)