Goofs

According to the canon of modern vampire stories, the scene where Abby comes in uninvited and begins to bleed to death shouldn't have happened: Owen had already invited her into the apartment in a previous scene, and if a vampire is invited in once they never have to be invited again. But this detail is a relatively new addition to vampire lore, and only applies to specific depictions. Historical mythologies have stated that all supernatural beings are unable to enter a house unless they are invited, but the first novel about vampires ('The Vampyre', John William Polidori , 1819) did not mention this requirement, which was first applied to vampires in 'Dracula' ( Bram Stoker , 1897) - but permission was required each time the vampire entered the house. Modern vampire stories in television and film ( True Blood Buffy: Im Bann der Dämonen ) changed this requirement, such that permission to enter need only be granted once. In 'Let Me In' (and in the source novel and film), permission must be granted every time. See more