Many “horror” games are starting to forget the difference between being horrified and being startled. Being horrified is to truly and profoundly fear something, to the point that just thinking about it sends shivers down your spine. Being startled is being briefly frightened by something because of a sudden movement. My brother can jump out of the closet and startle me, making me jump a bit, but that doesn’t mean he’s freaking Cthulhu.
Although, if your brother does look like Cthulhu you'll probably want to get serious medical attention.
A perfect example of this is the popular game “Dead Space”. Many people call it a horror game, as if it was the Mona Lisa of its genre. Yeah, I felt jumpy a couple times because I was scared, but I was never horrified. I swear, this game has more jump scares than a Halloween convention for Mexican jumping beans.
Sorry, adorable picture of a kitten, but you did not.
A necromorph jumping out of a ventilation system might scare me the first or second time, but it gets rather boring after the nineteenth time. If the main element of horror is compromised mostly of aliens jumping from behind a corner/ventilation system/the ceiling/boxes/the ground, pretending to be dead, the game is going to start to feel rather boring. True horror is getting into the players' mind, messing with the way they react to things, the way they see things, the way they think. True horror make us feel completely defenseless, make us feel totally and utterly alone, and I love it.