But it says life evolves because of natural selection, and I doubt natural selection would be very interested in eventually coming up with one species that would be nigh identical to the Engineers...I don't think it shits on Darwinism because Darwinism doesn't explain where the first piece of biological "cell" came from.
Either that's a huge coincidence, or the DNA was "programmed somehow" (not natural selection), or the Engineers were constantly intervening to "push" our ancestors' DNA in "the right direction" (not natural selection either).
(and whatever the case, I'd say cloning would have been a lot less troublesome.)