Originally Posted by Aleron Ives
It's the same way in horror movies: the things unseen were the most scary, but now it's all blood, gore, and visual effects.
That's the problem.
You can't just lump horror into one category anymore.
Now you have:
These are the "Monster" or "Ghost" movies where something creepy is killing or otherwise terrifying people. You get the jump scares and people disappearing - only to return dead, possesed or in a pod of some sort. Often, the kills are off screen and there isn't a lot of blood - except when another character finds a trail of it. In some of the more gory versions, they can cross over a bit into the slasher category. Usually, this category plays on common fears, like grave yards, the Devil, creepy paintings, trees, basements or the attic. Poltergeist and the original version of the Omen would be examples of this.
This is the "something isn't right" with a (House/Kid/Neighbor/Object) and there's usually a spell, curse or hidden burial ground involved. The whole movie leaves you uneasy, but there may not be a single death in the entire thing except maybe right toward the end. These movies often cross over a bit into mysteries. The Shining, The Other (or even The Others) or Turn of the Screw would be examples of this. These usually have somewhat of a slow boil to the climax.
These range from similar to horror movies with some violent deaths with very little blood to full on blood, guts and cgi-enhanced body part removal gore porn. These movies are seldom "scary" so much as "disturbing". They make you uncomfortable to watch as people have eyes and other parts removed on camera, or are impaled, chopped up or made into a wet mess. At the low guts end, you have Halloween on up to full on gore fests like Saw.
As a fourth, but smaller, category you have the "self aware" horror movies (usually from the slasher category) that play off the conventions of that type of film. These would include movies like the Scream and Cabin in the Woods. In these movies, characters actually reference the "rules" of such films. Friday the 13th Part VI also employed a bit of this.