When Lisa falls from the roof the creature grabs her from behind and when they both fall they are face to face.
When Lisa and Taffy are talking by the lockers, the same guy in a green and white shirt is seen walking away twice; and the same woman in a green dress is seen walking towards them twice.
When Lisa is painting her nails with white out, she puts it down and then the camera cuts to her holding it again in between her conversation with Michael.
When Lisa and Michael are talking by the lockers the same girl in glasses and a red top walks by them in the same direction twice.
When the creature chops Michael's penis off, blood splatters on Lisa's face, and is still there when she's taking Taff to the car, but when they arrive to the cemetery, Lisa's face and neck (and dress, seemingly) are completely clean.
On the creature's second session in the tanning bed, the eye protection worn going in disappears when he emerges.
When Lisa takes the creature into her bathroom to get cleaned up, Lisa closes the bathroom door while they are inside. During a shot of her explaining to him the items in her bathroom, you can see the door is clearly open in the background and shut again shortly after.
But the bathroom really has two entrances. When they entered the bathroom the door she closes is to Taffy's room. The door open is to Lisa's room.
But the bathroom really has two entrances. When they entered the bathroom the door she closes is to Taffy's room. The door open is to Lisa's room.
Although Lisa Frankenstein is set in 1989, a paperback copy of Poppy Z. Brite's Lost Souls is on one of Lisa's shelves. Lost Souls was released in 1992 in hardcover format.
In one outside shot of Lisa's house, palm trees can clearly be seen in the background despite the location of the film taking place in Illinois.