It works for teenage girls because they don't have a history of watching horror movies for 20-30 years like the more 'jaded' viewer might. They just started watching scary movies a couple of years ago so stuff like this might flip them out.
Imagine a pack of teenage girls raised on this garbage sitting in a theatre and watching The Exorcist or the original Evil Dead. Their heads would explode.

And so many PG-13 "horror" movies rely on cheap jump scares heavily, because they are limited in what they can show. Maybe it works for teenage girls 30 times, but I'm so tired of that predictable crap.

I'm sorry that people didn't respond better to your screenplay.

Blah blah blah.
What a bunch of whiney bitches.

Agree with your 'missed opportunity' assessment. The setting and subject matter and also the whole missing twin thing had great promise.
But this was not a good movie at all. Most of it due to a sloppy and lazy script. But the cheap jump scares didn't help.