What you don't see is scarier than what you do. Categorization is always kind of arbitrary, but people have called 'Preservation' a 'psychological thriller.' To me, psychological thriller basically means 'a horror movie without the blood.'
I'm lucky enough to say my day job is acting. I cut my teeth as a theater actor and playwright in New York.
I have a weak stomach. My wife is a doctor, so she finds it funny that I actually pass out when I get my blood drawn. I physically can't stand gore on screen. I can't stand blood and guts. Not for any puritanical/moral high-ground reason. I just don't want to black out.