Some really interesting information a lot of which clears up some questions we had already. Although there's a few issues overall with it that I seemed to find.
1)Aliens can't be killed during the special kill animations where they're mauling marines or whatever. That sucks flat-out. You should be able to save your buddies before they're killed.
2) Sounds. While some were spot on, the gunfire and Alien screams in particular I thought were pretty bad. Gunfire sounded fairly weak in areas, and Alien screams somewhat silly at times.
3)Animations for Aliens. No elaboration needed I guess, from what other people have said.
4)I saw a lot of dark areas in the MP level, but didn't see any flashlights being used by marines? (Might have missed it).
Overall, it was good, but like stated in the video comments section it seemed like a chore to play. The whole kill animation for Aliens against Marines seemed in particular to crap things up a bit. At the very least it should be changed to allow the player to stop it, whether by going over and pushing the Alien off his buddy, or by blasting it off, at a small cost of hp to the downed marine (Acid being dropped on the marine from dead Alien).
Just to note, I'm just pointing out the negative stuff I found in the hopes that some GBX employee might be reading this. There is a lot of good points I'm not mentioning like the correct Alien height, objective-based MP modes, graphics e.t.c.