Continuity mistake: After the credits, Cynthia Nixon is reading the story to the baby. When there's a transition between an establishing shot of the room and a close-up as she says "Baby Boo's nanny Henrietta says", her long bang in front of the left shoulder disappears. And a moment later, her right hand goes from the side of the book to the middle. (00:03:20)
Continuity mistake: The couple is reading newspapers at the breakfast table. When she replies to him that Old Willy hasn't had a picture in it in 20 years, the top of the newspaper is visible, but in the next shot the paper is folded. (00:04:15)
Continuity mistake: Picking up clothes to dress up Baby Bink for the shoot, the mom asks "Won't that look like we're trying to match his eyes?" The baby is 'reading' the book with the right page lifted, while it was flat when the sentence began. (00:06:45)
Continuity mistake: When the nanny leaves the room, Joe Mantegna is holding the book in his left and pointing with his right hand, only to be shown holding the book in both hands in the following shot. (00:13:10)
Continuity mistake: When the mother and the nanny are rushing back to the room where the phony photographers were, the housekeeper is doing some cleaning in a part of the hall to the side of the door. The butler opens the double doors, and she is suddenly already in view, trailing behind the trio. (00:14:30)
Other mistake: As Bink's dad looks at the ransom note, the note says "Mr. Cotwell, we have your baby. Put 5 Million $ in a trash bag in the alley behind the Ovaltine factory. No police." Then there are dramatic zoom jumpcuts on parts of the letter, ending with "By midnight." But that last part was not in the note at all. (00:15:00)
Continuity mistake: When Brian Haley absolutely decks Joe Pantoliano with a smack to the back of the head, the delighted baby is shown in two close-ups. In the second he is not in the same spot (look at the cloth behind his head) and his hair is combed differently across the forehead. (00:17:20)
Continuity mistake: Norby brings the baby to the bedroom as per Eddie's orders. We see him walk past the door holding a plush toy in his hand. When we see him in the room, the toy is under his armpit. (00:17:45)
Continuity mistake: From the kitchen table, Veeko tosses Baby Bink's storybook to Norby. He is tossing it with the back of the book on the left of the screen. When Joe Pantoliano catches a book tossed from stagehands, the book is turned the other way around. (00:20:05)
Continuity mistake: A pigeon coos outside the window when Baby Boo is at page 10 of the book. The baby actor turns a few pages bunched together, but in close-up he goes perfectly from 9-10 to 11-12. (00:23:00)
Continuity mistake: In the sequence when Baby Bink crawls off bed, Joe Pantoliano is resting on pillows positioned differently depending on the camera angle (the back pillow is either slumped low or propped higher). (00:23:25)
Continuity mistake: When Veeko spits his fingernails in front of the TV, Joe Mantegna and Brian Haley barely keep any continuity between shots (Haley's hand is turned with the palm up or down, Mantegna's pen hand is at different heights). (00:24:00)
Continuity mistake: Veeko spits his thumbnail in the same shot as he bites it, but then is still chewing it, and spitting it (with a sound as it 'lands'!) later. (00:24:15)
Continuity mistake: When the two kidnappers realise the baby is drooling on them from the skylight, Mantegna in the shot from above is holding the pen in his right hand. It was in his left a moment earlier. (00:25:10)
Revealing mistake: In the overhead shot of Eddie flipped back by the plank decking him in the jaw, look when he lands; the modest impact makes a chimney supposedly made of bricks wobble conspicuously. (00:26:05)
Continuity mistake: When the three stooges are about to jump from their hideout's roof, in the shot from behind Eddie has just one foot on the cloth placed on the edge of the building, while with the camera in front he has both feet on it, and Veeko's right foot fits too. (00:26:50)
Revealing mistake: When the three criminals jump from one roof to the other to chase the baby, Norby rolls during the landing and ends up against a metal chimney, which gets pushed aside, offering no resistance whatsoever. (00:26:55)
Continuity mistake: Despite making the jump with Eddie from one building to the next, the two goons come out of the original building they jumped away from. (00:27:00 - 00:28:20)
Continuity mistake: Eddie falls from the roof and breaks his fall on a window-mounted air conditioner. In the close-up through the window, no cable can be seen behind Joe Mantegna's head (supposed to be there as he took it down with his crotch earlier), but it is there in other shots. (00:27:00)
Continuity mistake: The pseudo-UPS guy has a hand truck he leaves by the elevator, but when the baby is crawling with the camera inside the elevator cabin, the cart is by the door of the old bat instead. (00:28:05)
Answer: It might have taken a while for them to find the keys to the crane as well as figuring out how to operate it. Once they did, they could get him down.