When Bruce and Patricia are crawling out of the elevator, Bruce's legs are still inside the elevator as he helps Patricia out of it. The shot changes, and his legs are out. It changes again, and his legs are back in.
Towards the end right after Pat jumps from the window washer and she is walking through the foggy, frozen room, you can hear her calling out everyone's name, but when she gets to Carol Anne her lips aren't moving.
In the scene where Pat and Bruce are in the garage being chased by the cars covered in ice and snow, the cars pull out to face them and you can see that the windscreens on the cars have tiny spy holes for the drivers to see through but in the next shot when the cars are still and parked, the spy holes have been covered up.
When Bruce and Patricia are shown in their room from outside the window, Bruce's black suit is laying on the end of the bed. Two shots later when they are shown from inside the room, Bruce goes to sit on the bed and the black suit is now laying in a different position on the bed.
After something strange happens in the bathroom as Donna gets ready for a party, Carol Anne and Donna walk into the main hall of the apartment. In the back, there is a large mirror. In the bottom, right-hand corner of the mirror, a crew member's bottom is shown wearing sandy brown dress pants.