"he showed a Gears of War demo with 100 Locust enemies running around."
Well, so much for the PS3 fanboys who said that Gears only looked so good because there were only a few enemies onscreen--especially since this one apparently looks much better.
So, from the trailer, you can definitely tell that there's at least one scene with Marcus and his dad ("if anything happens to me... find Maria..."
So, does this mean we'll get to see exactly what happened to Phoenix to make him abandon his post to help his dad? Damn! I want to play this so badly!
Also, when the game is finished, it will probably have taken them 9-10 months to make. My reasoning is that they very likely are using a slightly updated version of the UE3 that they used on Gears PC. This would free them up to focus only on the actual game elements, like the story and level design. So, even if they only started work on it right after UT3 launched, they could easily have it done and polished by November if they try.