In a martial arts film, you damn well better have a great fight choreographer. In a horror film, it's all about the makeup. There's nothing worse than finally revealing what your creature looks like and then realizing it's downright laughable.
SPOILER ALERT: Think M. Night's "Signs" with our favorite lunatic Mel Gibson. I think it's a great drama, not a horror film at all (which is one reason I think so many people hated it). The first reveal of the aliens was perfect. Remember the little video that Joaquin Phoenix watched of a birthday party and then the alien quickly walking by? Perfect.
Then Night butchers his entire movie with that retarded CGI alien at the end of the film. Downright laughable. Totally took you out of the whole finale.
SPOILER ALERT: Now think about films like "The Exorcist" and the Pazuzu demon. Scary ass shit. From Reagan's transformation to the white-faced Pazuzu. More recently, look at Ti West's "House of the Devil" and tell me the reveal of the Satanic creature isn't perfect. Again, he teases you with a side shot at first, and you can't help but ask yourself, what did I just see?
Makeup, can make or break a horror film. This includes blood spilling out of heads from a gunshot wound, or the pouring of blood out of one's slit throat. Sometimes less is more, but sometimes, more really kicks ass.
And the search for a makeup artist begins...