This is a very skilled distillation of all that makes the stalker enemy type and the classic slasher villain of the 80's, what they are.
If the Liminal Horror rules or a primer had room in the layout this could almost be considered a complete play resource which is to be applauded.
Set up, hook, history, and a ticking clock (which is so crucial for this kind of one-shot material) and I really think you have an easy pickup for Liminal Horror enjoyers.
Nice job!