Really great find! I love hearing/reading/watching behind-the-scenes stuff about the making of games, movies etc., sometimes even more so when they're projects like this that never ended up seeing the light of day.
I love the idea of an upgradeable base or stronghold that you had to venture out from into the rest of the world to find survivors and scavenge resources. It reminds me a bit of State of Decay, which I loved. Obviously all of the footage we have to go on is rough and unfinished (not to mention last-gen), but it certainly sounds like they had a lot of the right ideas, similar to how Creative Assembly knew the Alien franchise was fit for more than just shooters (and don't get me wrong, I love shooters, but a well-done Aliens RPG could have been something really unique).
Clearly watching this Sega just wanted to hedge their bets with the more proven and popular genre rather than because they thought Crucible actually looked bad, which is even more of a shame given all the stories that later came out about the way the funds and budget to A:CM were "managed". Maybe if they hadn't had to throw so much money at that we could have have actually seen a release for this. But alas, it was not to be.
Oh well, at the very least we got this cool little mini-un-making-of documentary out of it!