But then it sorta becomes Arthur C Clarke's 2001 Creation Myth.

Imagine that the Engineers NEVER made it to Earth... I know, I know, I shoulda coulda let it lie, but hear me out. I WAS SO WRONG. It wasn't a MODERN event nor was it an EARTH event. That opening scene where Engineers infest/seed an alien world with their Sacrificial Contribution (that might or might not have been an 'execution') should have been dated 132,098,003 ago on Tau Ceti 85396. And it should show a reverse-werewolf transformation where a raging pre-history bi-pedal BEAST rips off its brutal outer pelt to reveal a soft white intelligent modern human beneath, "Oh, gosh, darn, this is a pickle," he could crack. Then we'd have known, "These Engineers go waaaaaaaaaaaay back," and you can have as many space races as you want in a pre-Alien mini-series, not just Humanoid, but Space Elephaunt and Space Lobster and Space Worm... and Space Human. Yes, imagine a man brought up among this variety of creation, this cosmic jungle. Traded for food, skins. In the closing moments of the film, we see how OUR HUMANOID HERO crashes the LV-426 derelict and gets himself to Earth circa 25,000 BC the way Kyle Reece made his way back in time to save Sarah Connor. Some technical cine-excuse of narrative, some blinding ball of light. Then the whole Garden of Eden myth can be fully expanded out with mankind as a (literally) bestial race, having mated with the proto-humans who kept him warm and protected in their colony that first night of his arrival - in fact here is where I'd put the Spaihts chestburster lovemaking scene as the first proto-human gave birth to his 'soiled' creation some strangely liquid flesh beast pouring out of her abominal contration before crawling forward to its daddy and splitting up the back to reveal a CUTE BABY BOY within the gory remnants. But then it becomes something akin to Arthur C Clarke's 2001 story of a 'seeded inferior race made special' by THE APPLIANCE OF SCIENCE as it were. Hm......