Writing Techniques: To Explain, or Not to Explain?

So the other day, I read a review of Alien Vs. Predator (the movie version) in which the writer of said review (author of the webcomic Lovecraft is Missing, which I have mentioned in the past and is about exactly what it says it is about) complained about the "watering down" of the Aliens and Predators by explaining and exploring them. The whole point, he says, is that they're scary because we don't really understand them; going into the life cycle of the Aliens or the culture of the Predators takes the teeth out of them.

Speaking as someone who examines worldbuilding for the sake of doing so, I can see his point, but I must also disagree to some degree. While the scariest thing imaginable is the thing you don't understand at all, partly because you don't know what it can and can't do, that doesn't mean something you do understand is totally deprived of its scare factor.

Just because you know that a xenomorph is basically just a giant ant/parasitic wasp/velociraptor hybrid that is also bulletproof doesn't make it not scary; for crying out loud, even a simple bulletproof velociraptor would be pretty darned scary if you were the guy it was chasing. Whether or not it's a "cheap" scare depends on how it's used.

Also, speaking as someone who is a (wannabe) author, I can understand another motivation for revealing details of a movie monster: In order for it to make sense in a science fiction context, the creators of the monster have to know all the details, regardless of whether they reach the film or not. And I can imagine that, if they had made all those Alien movies (for crying out loud, how many are there now?) and never got to elaborate or otherwise explore their nature, they would probably have gone completely bonkers from wanting to share.

I suppose also that part of my perspective comes from being a science fiction reader (and moreover a science weirdo); I like to know about things, usually for the sake of knowing about them. And I'll tell you what-reading the stupid Zombie Survival Guide actually wasn't funny at all-it scared the freaking heck out of me, and gave me the heebiejeebies so badly I didn't sleep that night. There's also a horror story, "The Autopsy" (by Michael Shea), which initially looks like it might just be a story about a particularly weird serial killer; but then, it looks like it might be a story about a vampire; but the real answer (which I won't spoil), revealed after several more twists and turns, is rather creepier. But it would not have been if we'd never found out the answer-it'd just have been a frustrating buildup of suspense.

The ultimate answer to whether or not something should be explained depends on numerous factors. Time, the effect you're going for, and how well you can work exposition into stories all are part of it.

(He also complains that the Predators are "just like us," something which I think could be addressed, but I'll get to that some other time.)

-Signing off.