Galaxy of Terror, Mutant (NSFW), Contamination and the joy of cheap alien knockoffs. Prefer the sequel? Here's Aliens remade under the name "Terminator 2". Sadly one take on the franchise that will not be seeing the light of day is Alien Identity, a fan film recently shut down by a cease and desist from Fox. Meanwhile the Neil Blomkamp Alien film continues to incubate.
"By the way, it's not in the goddamed cat and it's not in Newt, either. I would never be that cruel."
Dark Angel is a rip-off of Heinlein's Friday, which I completely agree with. Cameron has been successfully sued by Harlon Ellison before for blatantly ripping off his ideas. Then again the sci-fi word is a static world of either super-humans/machines/aliens/time-trave/alternate dimensions.