Yep, I know the one - thanks, worked perfectly!
One of the videos showed Snakemen and Chryssalids. Not sure if any of the maps include them - the briefing videos make it pretty clear that the primary enemies are the Sectoids, the leader of which is called "the Nexus".
One is mostly made up of sketches interspersed with CG animation. Notable features include a female voiced by a man, and a Sectoid ship that looks exactly like an Imperial Star Destroyer.
The videos also talk about a data extraction unit device you have in your inventory, a little computer-type thing. You probably have to use this on certain buttons/terminals, which'd explain why my team mate knew how to activate them but I didn't. Either that or the team mate really knows stuff my soldier didn't (one of the briefing videos makes it sound like she's brought along for brains rather then combat ability).
There's a UFOpedia animation for a decent selection of weapons; nothing too fancy (the usual rifles/plasmas). The freeze gun apparently shoots helium, and there's a guided launcher in there too. Much to my annoyance, the awesome gun that looked like an expandable blasterbomb shell doesn't make an appearance... More to my amazement, I can't find a copy of the picture of it anywhere other then on my hard drive, though I'd be surprised if no one knows the one I'm talking about. Will have to put our Alliance site section back in order.
Some maps appear to have Ascidians (or however it's spelt) assigned to them, but it doesn't look like there are actual models for the engine to load (even the briefing videos only show concept-art type stuff). The Microprose logo is still on some of the videos, suggesting these particular builds haven't been touched since they were bought out (though as I said above, I don't think *any* builds were touched since then).
There's probably enough content to get a pretty good picture as to how the overall plot was going to go, though I'm not seeing much as to how the relationship with the Ascidians would progress.