Great Work!!!!
Loved the theme!!
I mean honestly we need more stuff like this in for NGs.
The work up and set up where spotless. The way you could tell the main characters thoughts also helped a bunch. The friend was kind of freaky to be honest he had a picture of what looks like the cousin of the dead guy.
What i would suggest for the next one get better timing on the soundtrack. The fact of the matter is that when you are scared of something it is usually something you dont see directly while you can still hear it coming, you can still see its shadow approach, you can still recognize its heavy breathing and sudden actions in this case.
I would suggest you watch old horror movies not the new ones and see what they do to get the audience ready for the scare without showing the monster in the scene then, for example, he will pop out and go for the kill once the character thinks he is safe. Good work but definitely looking forward to your next work.
I'l give you a 7/10 for now but you have a guarenteed review for your next flash.