Position of Mario's hands on Giulia's back is different in the movie's ending shot from the previous one.
Despite being referred to as the "Half Moon Killer", the medallions the perp leaves are actually crescent shaped.
Kathy is still moving her eyelashes after being dead.
In scenes where the characters are driving vehicles, we can see that the interior mirrors are almost always angled slightly above average to the left, there probably wasn't good enough equipment for convincing mirror trick or grease to smudge reflective surfaces (such as is done with the silver details of Rambo's motorcycle in Syndicate Sadists, during the credits scene, film also directed by Lenzi).