I'm not keen on this new backstory business. Yes, it's always been a load of nonsense that doesn't matter in the grander scheme of things, but still...genetic modification? Come on.
Firstly, you're telling me that the organisation that originally pinned down this nigh-uncontrollable alien decided that a) it might make a good weapon, and b) it needed to be more dangerous? Potentially actually uncontrollable?
Secondly, it undermines the whole idea of Nemesis originally being an overwhelming force that was eventually controlled against the odds. Now humanity's meddling has made something that was nearly unstoppable even stronger?
I'd have preferred it if they'd decided Nemesis was mutating of its own accord, if they really had to justify the rebrand. It's an otherworldly eldritch horror; it can do whatever, regardless of how any real creatures work.