Decoys, Species, and Lifeforce are about aliens disguised as beautiful, attractive women who use their sex appeal to seduce men into having sex with them for their own gain. In the case of Decoys and Species, they're trying to mate with the human race to save/expand their own. In the case of Lifeforce, they're trying to bring about the galactic rapture. These movies are very much guilty pleasures for me, but only because they share one crippling, fatal flaw: the aliens aren't the protagonists.
If I learned anything from premium television, anime, comic books, and video games, its that, in stories like this, the villains are always the most interesting characters, especially if they're superhuman femme fatales (and vice-versa). So why not make them the protagonist? I wouldn't mind if we're talking about a slasher flick or torture porn or (if that's not a good enough description for them, then) whatever the hell Saw is supposed to be. However, in a thriller about horny, humanoid, creatures who've weaponized sex against us, do you really expect for me to root for the cockblockers? The boring, white, cardboard-cutout, protagonist I see in every other movie?
Anyone who's read Vampire Cheerleaders will agree with me on this one. It's a comedic web comic (or web manga, given the premise) that's exactly what it says: a story about undead bloodsuckers who just happen to be spoiled, bitchy, cheerleader stereotypes. It's slice of life gone bloody wrong; within the first volume our protagonists have "initiated" a naive girl into their ranks, enthralled her family and turned the hero antagonist into their slave.
These girls are straight-forward villains and, if it were a different story in a different genre, your first instinct would be to root against them. Yet, by the third volume, when the heroes are competent enough to stop them, the fandom found themselves rooting for the vampires, despite the horrible things they've done. This is what happens when you've created despicable villains who are also very likable characters and made them the protagonists. Tell me you haven't watch a movie or TV show where the villains were more likable than the heroes (okemon-Pay) and you wished the story was about them.
Going back to the gutter with a fresh new suit, the aliens in Decoys are simply trying to protect their race from going extinct. They didn't mean to leave a trail of frozen corpses, but if they must... Meanwhile, the "heroes" are just hormone-crazed college students who realized too late that these girls are not what they seem. Am I supposed to believe that, at the drop of a hat, they go from the annoying kids you're more likely to find in an episode of Degrassi to a group of alien exterminators? Screw that!
Granted, if the villains of these movies were the true protagonists, the ending would either be tragic for the villains or horrendous for humanity. On the other hand, aren't thrillers supposed to have bittersweet endings at the very least? Perhaps I should be looking for a sci-fi black comedy instead? I guess it is too much to ask for junk food to be compelling. If it wasn't, we wouldn't have guilty pleasures like these and we wouldn't be asking ourselves how we can make them as "decent" as the stuff we normally enjoy. If you enjoyed it for what it is, then who cares what others think, right?
...On the subject of horror franchises making a comeback, is a third Decoys movie or a television series really too much to ask?