If the hanged girl was facing the door, how does it face the window in the photo taken from the balcony of the neighboring building.
In the scene when Cassinelli and Ralli are looking at a strip of film footage, they repeatedly stop the projector to pause on a single frame. However, the shadow of the projector plainly reveals that it is still rolling.
When Cassinelli and Ralli are using a film projector, they ask the operators to reverse the film. The film starts again at the footage asked for, without rewinding.
Silvia's actress is obviously older than 15, although her character isn't supposed to be older than that age.
The policeman's hand that was cut with a cleaver is clearly fake.
Talenti's cut head is obviously a doll head.
If the killer already killed a driver while chasing the attorney, there was no reason not to kill the old man while killing the woman.