The THEME is: You need to destroy life if you want to create some.
The SJ kill himself to give birth to life.
Nothing tell us that the worms are still alive and they are probably very much dead. The black goo just find a way to then interact with the DNA of the worms or whatever ideas you wanna invent. I'm not here to discuss this but nothing states clearly: Mutation.
The SJ head is kinda a total different topic. I don't want to theorize on it, it just looks stupid IN MY OPINION.
It for sure shows the danger. Just like chet show how he's the danger in AVP-R.
But since this affect characters I don't really gives a shit because they said like 6 - 7 lines and had a 2 mins screentime and were mostly moron it simply made me react like "oh! finally".
ALIEN made me feel the danger much before the Facehugger scene.
And what was Weyland motive persona then if it's not to acquire immortality (and how could that help?)
For me it didn't work, this was lazy, cliché, and as every slasher happens in a total random way that trigger a chain of unthinkable events that serves no real purpose apart getting a rid of some characters.
My opinion, you won't change it.
For me Admitting Prometheus is a good film would make me admit that both AVP are too.
And I can't.
