At the end of the movie you can see the bottle of spray paint rolling down the stairs and landing on the pavement. In the next shot, when Helen's body hits the pavement the bottle is gone.
After Madeleine drinks the potion, Lisle pins a 'brooch' to the right side of her dress. When Madeleine goes to the hall to leave it's on the left side of her dress.
Helen falls backwards into the fountain after being shot, but gets up from a face-down position.
Helen has had a hole blown through her stomach by the time the "shovel fight" has begun. As Ernest leaves the scene, you see the shadows of the women fighting, only now the hole is in Madeleine's shadow, not Helen's.
When Madeline and Helen meet in Madeline's dressing room, they kiss one another on the cheek. Madeline leaves a large bright red lip print on Helen's upper cheek. In the next shot, the print has moved down toward her chin area.
The pool is illuminated from below, yet no light shines up through the large dark hole in Helen's abdomen.
When Ernest runs through ER looking for a doctor a short scene shows a CPR in action. On the ECG monitor a flat line can be observed, nonetheless the doctors try to revive the patient with an electric defibrillator. ECG flat line cannot be treated by defibrillation.
If the shotgun blast (slowed by air resistance) is sufficient to send Helen flying, the recoil should also hurl Madeline backwards - and by a greater amount.
Lisle (the first name of the von Rhuman character) is the German-Austrian diminutive of Elizabeth. It is more correctly spelled "Liesl."
Gallons of water flow out of Helen's new hole, but there's nowhere it could have come from. Her upper torso has not been hollowed out.
When Madeline drinks the potion, she holds the vial to her lips for several seconds after the CGI liquid pours into her mouth. She is eagerly trying to obtain every last drop and could also be savoring it.
The moral of the movie may be that eternal youth is more of a curse than a blessing, yet during the ballroom scene we meet a large number of immortals who are having no problems at all. Obviously the moral would not apply to every single person.
Just before Madeline gets her head knocked down by Helen, you can see her body shift. This is because of body double replacement.
Shortly before Helen is shot, Bruce Willis' grayish makeup can be seen to end at his jawline, allowing a big patch of rosy skin to show through.
Just after a drugged Madeline falls face-down in her dinner (according to Helen's plan), all the candle flames are wafted by the rapid passage of the camera up the table.
When Ernest pushed Madeline down the stairs, Meryl's robotic head can clearly be seen.
Helen is supposed to be 50 years old for the majority of the film. When she is meeting one-on-one with the therapist, you can briefly see her patient file, where her birth year is listed as 1951. This would make her 26-27 at the open, 33-34 during the therapy, and 40-41 during the rest of the film.
When Ernest has crashed into Lisle's pool he was supposed to find the potion vial floating intact. When the ending was changed this was no longer needed and they digitally removed the potion vial from his hand either digitally or by editing. Yet when Ernest has gotten out of the pool and Jim Morrisson says "That was pretty neat!" Ernest walks to the exit and you can still see him holding the potion vial in his left hand.
Whe Madeline arrives at lisle's en she gets to sit on the couch, the table the potion will be balancing on, seems to have no glass surface, but when the potion is placed on the table, all of a sudden there is a glass surface.
When Ernest starts to bolt with the potion, Lisle says "Tom, Dick, Harry, get the potion from him!" He picks up the dagger she stabbed him with. As he does, you see her reflection on the glass table. Her lips do not move when she says those words.
When Ernest is looking at the picture in front of the mirror, the top of a crew member's head is clearly visible moving in the bottom left corner of the mirror.
After the shovel fight Mad confronts Hel and says: "Admit you thought I was Cheap". As she says this, Mad points her finger towards Hel, but as the take changes Mad's facial expression is completely different.
At the ballroom party towards the end of the movie, Andy Warhol and Elvis Presley are shown as two of the "immortals" - but appear as they did late in life, and not as they were in their flush of youth.
When Ernest is on the phone with Helen, Madeline comes up behind him and yells at him while the connection is still open, so Helen has to hear her. But later, when Helen gets there, she doesn't believe that Madeline is still alive.