I don't see them retconning Aliens at all.
I'm also one of those who think the world is not coming to an end because the movie is not exactly the way I wanted it to be even because it's not my movie.
Those giant, hollowed-out tree stumps look pretty ominous as well.
Seeing the trailer 4 that one made me look forward to that scene with Shaw stumbling around in those 5th Element type bandages.
Just to drum up the matter, alien doesn't have to mean naturally occurring evolved organism.
Talking about the xenomorph as the end allis like talking saying their are only bobcats in the feline species.
Looks a bit like the stuff from independence day.