When Freeway is sitting on the window seat, the window behind him is open, then when the Harts are going to try to escape through that window, it's closed.
When the Harts are running away from Ciro, they run past the car. In the very next shot, they are not yet to the car when they come out from hiding behind a tree.
Frank tells Ciro to look for the Harts before Ciro tells him that the Harts are missing.
Obvious stunt for Robert Wagner in the fight in the living room.
Millie Perkins' fingernails can be seen as short. In the close-up of the hands handling Freeway's dog toy, the nails are much longer.
Ciro pulls out the wires on the mobile phone in the Rolls Royce so that the Harts can't use it. Later, Max returns home in the station wagon, but the Harts don't try to use the mobile phone in that car.
Brenda turns on the gas flame under the tea kettle in the kitchen, when she leaves the kitchen it's still on.
Vito Scotti's pizza man character "Guido" is incorrectly listed in the closing credits at "Vito."