Revealing mistake: When the demon breaks into the jail and the cop is standing behind him. When the camera turns back on to the demon, if you look close you can see the zipper in the left hand side of the demon's suit. (01:08:45)
Revealing mistake: In the closeup of the demon monster you can see the contact in his eye.
Revealing mistake: During the final showdown, where the Creeper is holding Darry hostage, as the camera zooms in towards the Creeper's face when it is screaming intensely, you can see the nose and teeth of the actor underneath the make-up/suit.
Answer: Since the Creeper needs various body parts i.e. eyes to see, lungs to breathe, it would also need to eat the hearts of its victims for its own heart to keep beating. Or she could mean that the Creeper is essentially devoid of all emotions as it keeps attacking anybody that has the body parts that it needs to extend its own life.