Allow me to rant for a minute...
I've done some horror stuff (nothing uploaded here yet), but I think most people just kind of overlook horror-oriented costumes for a couple of reasons:
1) I think a lot of people think it's not enough of a challenge to "just" be some gorey/bloody/gooey/scary costume, and...
2) A lot of horror costumes end up being just that... or at least, that's all people do with them. They get some old clothes, a hockey mask, and all of a sudden they're supposed to be Jason, when they're really just some guy in old clothes and a hockey mask. What I mean is, for whatever reason, it seems like with horror costumes especially, the discrepancy between the actual character and the person's costume of that character is consistently very large. Hardcore cosplayers usually chose a more complex and difficult costume (nevermind sticking to anime and video games most of the time), and hardcore horror fans seem to have lower standards for accuracy. This is just a trend I've noticed, and I'm not digging on anyone, I'm just sayin'. The quality just isn't there.
is bad picture of me as Samara. Now, this isn't an ego thing, but I'm the only
Samara I've seen in however many years since The Ring
came out that actually had makeup on the arms and legs. SURELY someone out there can do a better version than I did, but you don't see them. Why? I don't know. What you do
see are people with a black wig and a white dress. Now, you can argue that they're doing the Sadako version or w/e, but my point is, I spent at least a week just on weathering the dress to make it look like the movie version (there's a lot you can't see in that terrible pic). It wasn't expensive, it wasn't hard, and I probably could've done the same amount of work in 2 days if I was pressed for time. People just don't put in the effort, from what I've seen.
Horror is kind of hit-or-miss anyway, meaning people either seem to love it or hate it, but I really think if people put more into their costumes, it'd be easier to bridge the gap and make horror costumes a more accepted genre in the cosplay world. After all, a well-made costume is a well-made costume, regardless of what or who it is. Show me a Freddy Krueger that doesn't look like some guy with strawberry jelly on his face and a handful of screwdrivers, and I guarantee you more people will take horror costumes seriously.